Apparatus for transmitting broadcast signals, apparatus for receiving broadcast signals, method for transmitting broadcast signals and method for receiving broadcast signals

ABSTRACT

The present invention proposes a method of transmitting a broadcast signal. The method of transmitting a broadcast signal according to the present invention proposes a system capable of supporting a next-generation service in an environment that supports next-generation hybrid broadcasting which uses a terrestrial broadcast network and an Internet protocol network. In addition, the method proposes an efficient signaling scheme that can embrace both the terrestrial broadcast network and the Internet protocol network in an environment that supports next-generation hybrid broadcasting.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International ApplicationNo. PCT/KR2016/000058, filed on Jan. 5, 2016, which claims priorityunder 35 U.S.C. 119(e) to U.S. Provisional Application No. 62/100,081,filed on Jan. 6, 2015, and to U.S. Provisional Application No.62/119,262, filed on Feb. 22, 2015, all of which are hereby expresslyincorporated by reference into the present application.

TECHNICAL FIELD

The present invention relates to an apparatus for transmitting abroadcast signal, an apparatus for receiving a broadcast signal andmethods for transmitting and receiving a broadcast signal.

BACKGROUND ART

As analog broadcast signal transmission comes to an end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

DISCLOSURE Technical Problem

That is, a digital broadcast system can provide HD (high definition)images, multichannel audio and various additional services. However,data transmission efficiency for transmission of large amounts of data,robustness of transmission/reception networks and network flexibility inconsideration of mobile reception equipment need to be improved fordigital broadcast.

Technical Solution

The present invention provides a system capable of effectivelysupporting future broadcast services in an environment supporting futurehybrid broadcasting using terrestrial broadcast networks and theInternet and related signaling methods.

Advantageous Effects

The present invention can control quality of service (QoS) with respectto services or service components by processing data on the basis ofservice characteristics, thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same radio frequency(RF) signal bandwidth.

The present invention can provide methods and apparatuses fortransmitting and receiving broadcast signals, which enable digitalbroadcast signals to be received without error even when a mobilereception device is used or even in an indoor environment.

The present invention can effectively support future broadcast servicesin an environment supporting future hybrid broadcasting usingterrestrial broadcast networks and the Internet.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a receiver protocol stack according to an embodimentof the present invention.

FIG. 2 illustrates a relation between an SLT and service layer signaling(SLS) according to an embodiment of the present invention.

FIG. 3 illustrates an SLT according to an embodiment of the presentinvention.

FIG. 4 illustrates SLS bootstrapping and a service discovery processaccording to an embodiment of the present invention.

FIG. 5 illustrates a USBD fragment for ROUTE/DASH according to anembodiment of the present invention.

FIG. 6 illustrates an S-TSID fragment for ROUTE/DASH according to anembodiment of the present invention.

FIG. 7 illustrates a USBD/USD fragment for MMT according to anembodiment of the present invention.

FIG. 8 illustrates a link layer protocol architecture according to anembodiment of the present invention.

FIG. 9 illustrates a structure of a base header of a link layer packetaccording to an embodiment of the present invention.

FIG. 10 illustrates a structure of an additional header of a link layerpacket according to an embodiment of the present invention.

FIG. 11 illustrates a structure of an additional header of a link layerpacket according to another embodiment of the present invention.

FIG. 12 illustrates a header structure of a link layer packet for anMPEG-2 TS packet and an encapsulation process thereof according to anembodiment of the present invention.

FIG. 13 illustrates an example of adaptation modes in IP headercompression according to an embodiment of the present invention(transmitting side).

FIG. 14 illustrates a link mapping table (LMT) and an RoHC-U descriptiontable according to an embodiment of the present invention.

FIG. 15 illustrates a structure of a link layer on a transmitter sideaccording to an embodiment of the present invention.

FIG. 16 illustrates a structure of a link layer on a receiver sideaccording to an embodiment of the present invention.

FIG. 17 illustrates a configuration of signaling transmission through alink layer according to an embodiment of the present invention(transmitting/receiving sides).

FIG. 18 is a block diagram illustrating a configuration of a broadcastsignal transmission apparatus for future broadcast services according toan embodiment of the present invention.

FIG. 19 is a block diagram illustrating a bit interleaved coding &modulation (BICM) block according to an embodiment of the presentinvention.

FIG. 20 is a block diagram illustrating a BICM block according toanother embodiment of the present invention.

FIG. 21 illustrates a bit interleaving process of physical layersignaling (PLS) according to an embodiment of the present invention.

FIG. 22 is a block diagram illustrating a configuration of a broadcastsignal reception apparatus for future broadcast services according to anembodiment of the present invention.

FIG. 23 illustrates a signaling hierarchy structure of a frame accordingto an embodiment of the present invention.

FIG. 24 is a table illustrating PLS1 data according to an embodiment ofthe present invention.

FIG. 25 is a table illustrating PLS2 data according to an embodiment ofthe present invention.

FIG. 26 is a table illustrating PLS2 data according to anotherembodiment of the present invention.

FIG. 27 illustrates a logical structure of a frame according to anembodiment of the present invention.

FIG. 28 illustrates PLS mapping according to an embodiment of thepresent invention.

FIG. 29 illustrates time interleaving according to an embodiment of thepresent invention.

FIG. 30 illustrates a basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 31 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

FIG. 32 is a block diagram illustrating an interleaving addressgenerator including a main pseudo-random binary sequence (PRBS)generator and a sub-PRBS generator according to each FFT mode accordingto an embodiment of the present invention.

FIG. 33 illustrates a main PRBS used for all FFT modes according to anembodiment of the present invention.

FIG. 34 illustrates a sub-PRBS used for FFT modes and an interleavingaddress for frequency interleaving according to an embodiment of thepresent invention.

FIG. 35 illustrates a write operation of a time interleaver according toan embodiment of the present invention.

FIG. 36 is a table illustrating an interleaving type applied accordingto the number of PLPs.

FIG. 37 is a block diagram including a first example of a structure of ahybrid time interleaver.

FIG. 38 is a block diagram including a second example of the structureof the hybrid time interleaver.

FIG. 39 is a block diagram including a first example of a structure of ahybrid time deinterleaver.

FIG. 40 is a block diagram including a second example of the structureof the hybrid time deinterleaver.

FIG. 41 is a diagram illustrating an example of a protocol stack forsupporting a broadcast service according to the present invention.

FIG. 42 is a diagram illustrating another example of the protocol stackfor supporting the broadcast service according to the present invention.

FIG. 43 is a diagram illustrating an example of a transport layer of thebroadcast service according to the present invention.

FIG. 44 is a block diagram illustrating the whole configuration of theemergency alert system according to an embodiment of the presentinvention.

FIG. 45 illustrates syntax of EAT information according to an embodimentof the present invention.

FIG. 46 illustrates syntax of an emergency alert message according to anembodiment of the present invention.

FIG. 47 illustrates syntax for automatic channel tuning informationaccording to an embodiment of the present invention.

FIG. 48 illustrates syntax for NRT service information according to anembodiment of the present invention.

FIG. 49 illustrates embodiments of syntax of a section table fortransmitting an emergency alert message according to the presentinvention.

FIG. 50 illustrates embodiments of syntax of a section table fortransmitting an emergency alert message according to the presentinvention.

FIG. 51 illustrates an embodiment of configuring a packet to transmit anEAT without changing the form according to the present invention.

FIG. 52 illustrates an embodiment of configuring a packet to transmit anemergency alert message in the form of separate information rather thana section table according to the present invention.

FIG. 53 is a block diagram illustrating another embodiment of theemergency alert system for transmitting/receiving the emergency alertinformation according to the present invention.

FIG. 54 is a block diagram illustrating another embodiment of theemergency alert system for transmitting/receiving the emergency alertinformation according to the present invention.

FIG. 55 is a block diagram illustrating another embodiment of theemergency alert system for transmitting/receiving the emergency alertinformation according to the present invention.

FIG. 56 is a block diagram illustrating another embodiment of theemergency alert system for transmitting/receiving the emergency alertinformation according to the present invention.

FIG. 57 illustrates an embodiment of syntax of an emergency alertmessage transmitted through a signaling channel.

FIG. 58 is a block diagram illustrating another embodiment of theemergency alert system for transmitting/receiving the emergency alertinformation according to the present invention.

FIG. 59 illustrates an embodiment of syntax for signaling an emergencyalert transmitted through a signaling channel.

FIG. 60 is a flowchart illustrating an operation method of a broadcasttransmitter according to an embodiment of the present invention.

FIG. 61 is a flowchart illustrating an operation method of a broadcastreceiver according to an embodiment of the present invention.

FIG. 62 illustrates a conceptual view of a link layer packet accordingto the present invention.

FIG. 63 is a diagram illustrating examples of respective fields includedin a fixed header and an extended header of a link layer packet.

FIG. 64 illustrates the fixed header and the extended header in the formof syntax.

FIG. 65 is a diagram illustrating definition of values assigned to asignaling_class field of a link layer packet header in the form of atable according to the present invention.

FIG. 66 is a diagram illustrating definition of values assigned to aninformation_type field of the link layer packet header in the form of atable according to the present invention.

FIG. 67 illustrates an example of syntax of a payload a packet for anemergency alert when a link layer packet is the packet and an emergencyalert message is transmitted using the payload of the packet.

FIG. 68 is a flowchart illustrating one embodiment of a method ofreceiving and processing an emergency alert packet in a broadcastreceiver according to the present invention.

FIG. 69 illustrates an example of syntax of a payload a packet for anemergency alert when a link layer packet is the packet and connection(or link) information of an emergency alert message is transmitted usingthe payload of the packet.

FIG. 70 is a flowchart illustrating an embodiment of a method forreceiving and processing a link layer packet in a broadcast receiveraccording to the present invention.

FIG. 71 illustrates an example of syntax of a payload a packet for anemergency alert when a link layer packet is the packet and automatictuning information related to the emergency alert is transmitted usingthe payload of the packet.

FIG. 72 is a flowchart illustrating an embodiment of a method forreceiving and processing a link layer packet in the broadcast receiveraccording to the present invention.

FIG. 73 illustrates an example of syntax of a payload a packet for anemergency alert when a link layer packet is the packet and NRT serviceinformation related to the emergency alert is transmitted using thepayload of the packet.

FIG. 74 is a flowchart illustrating an embodiment of a method forreceiving and processing a link layer packet in the broadcast receiveraccording to the present invention.

FIG. 75 is a block diagram illustrating an embodiment of the broadcastreceiver for supporting an emergency alert service according to thepresent invention.

FIG. 76 is a block diagram illustrating another embodiment of thebroadcast receiver for supporting the emergency alert service accordingto the present invention.

FIG. 77 is a block diagram illustrating another embodiment of thebroadcast receiver for supporting the emergency alert service accordingto the present invention.

FIG. 78 is a diagram illustrating an FIC according to an embodiment ofthe present invention.

FIG. 79 is a diagram illustrating a service category according to anembodiment of the present invention.

FIG. 80 is a diagram illustrating a form in which one frequency isshared by two broadcasters according to an embodiment of the presentinvention.

FIG. 81 is a diagram illustrating Emergency_Alert_Table( ) according toan embodiment of the present invention.

FIG. 82 is a diagram illustrating a flow of a broadcast receiveraccording to an embodiment of the present invention.

FIG. 83 is a diagram illustrating a flow of a broadcast receiveraccording to an embodiment of the present invention.

FIG. 84 is a diagram illustrating syntax related to an EAC added to PLSaccording to an embodiment of the present invention.

FIG. 85 is a diagram illustrating a form in which only the WARN messageis transmitted through the EAC according to an embodiment of the presentinvention.

FIG. 86 is a diagram illustrating a form in which a WARN message and aCAP message are transmitted through an EAC according to an embodiment ofthe present invention.

FIG. 87 is a diagram illustrating a link layer header according to anembodiment of the present invention.

FIG. 88 is a diagram illustrating a signaling_class field according toan embodiment of the present invention.

FIG. 89 is a diagram illustrating an information_type field according toan embodiment of the present invention.

FIG. 90 is a diagram illustrating syntax related to a WARN message addedto PLS according to an embodiment of the present invention.

FIG. 91 is a diagram illustrating a form in which a WARN message istransmitted through LLS according to an embodiment of the presentinvention.

FIG. 92 is a diagram illustrating PLS in a case in which signalinginformation for a WARN message is transmitted through an EAC accordingto an embodiment of the present invention.

FIG. 93 is a diagram illustrating an EAT that includes signalinginformation for a WARN message according to an embodiment of the presentinvention.

FIG. 94 is a diagram illustrating a form in which signaling informationfor a WARN message is transmitted through an EAC according to anembodiment of the present invention.

FIG. 95 is a diagram illustrating PLS that includes signalinginformation for a WARN message according to an embodiment of the presentinvention.

FIG. 96 is a diagram illustrating a form in which a WARN message istransmitted through an LCT session according to an embodiment of thepresent invention.

FIG. 97 is a diagram illustrating an EAT in a case in which signalinginformation for a WARN message is transmitted through an EAC accordingto an embodiment of the present invention.

FIG. 98 is a diagram illustrating a form in which signaling informationfor a WARN message is transmitted through an EAC according to anembodiment of the present invention.

FIG. 99 is a diagram illustrating a form in which a WARN message istransmitted through a dedicated PLP or a dedicated LCT session accordingto an embodiment of the present invention.

FIG. 100 is a diagram illustrating a broadcast transmission methodaccording to an embodiment of the present invention.

FIG. 101 is a diagram illustrating a broadcast reception methodaccording to an embodiment of the present invention.

BEST MODE

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although the terms used in the present invention are selected fromgenerally known and used terms, some of the terms mentioned in thedescription of the present invention have been selected by the applicantat his or her discretion, the detailed meanings of which are describedin relevant parts of the description herein. Furthermore, it is requiredthat the present invention is understood, not simply by the actual termsused but by the meanings of each term lying within.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, anultra high definition television (UHDTV) service, etc. The presentinvention may process broadcast signals for the future broadcastservices through non-MIMO (Multiple Input Multiple Output) or MIMOaccording to one embodiment. A non-MIMO scheme according to anembodiment of the present invention may include a MISO (Multiple InputSingle Output) scheme, a SISO (Single Input Single Output) scheme, etc.

FIG. 1 illustrates a receiver protocol stack according to an embodimentof the present invention.

Two schemes may be used in broadcast service delivery through abroadcast network.

In a first scheme, media processing units (MPUs) are transmitted usingan MMT protocol (MMTP) based on MPEG media transport (MMT). In a secondscheme, dynamic adaptive streaming over HTTP (DASH) segments may betransmitted using real time object delivery over unidirectionaltransport (ROUTE) based on MPEG DASH.

Non-timed content including NRT media, EPG data, and other files isdelivered with ROUTE. Signaling may be delivered over MMTP and/or ROUTE,while bootstrap signaling information is provided by the means of theService List Table (SLT).

In hybrid service delivery, MPEG DASH over HTTP/TCP/IP is used on thebroadband side. Media files in ISO Base Media File Format (BMFF) areused as the delivery, media encapsulation and synchronization format forboth broadcast and broadband delivery. Here, hybrid service delivery mayrefer to a case in which one or more program elements are deliveredthrough a broadband path.

Services are delivered using three functional layers. These are thephysical layer, the delivery layer and the service management layer. Thephysical layer provides the mechanism by which signaling, serviceannouncement and IP packet streams are transported over the broadcastphysical layer and/or broadband physical layer. The delivery layerprovides object and object flow transport functionality. It is enabledby the MMTP or the ROUTE protocol, operating on a UDP/IP multicast overthe broadcast physical layer, and enabled by the HTTP protocol on aTCP/IP unicast over the broadband physical layer. The service managementlayer enables any type of service, such as linear TV or HTML5application service, to be carried by the underlying delivery andphysical layers.

In this figure, a protocol stack part on a broadcast side may be dividedinto a part transmitted through the SLT and the MMTP, and a parttransmitted through ROUTE.

The SLT may be encapsulated through UDP and IP layers. Here, the SLTwill be described below. The MMTP may transmit data formatted in an MPUformat defined in MMT, and signaling information according to the MMTP.The data may be encapsulated through the UDP and IP layers. ROUTE maytransmit data formatted in a DASH segment form, signaling information,and non-timed data such as NRT data, etc. The data may be encapsulatedthrough the UDP and IP layers. According to a given embodiment, some orall processing according to the UDP and IP layers may be omitted. Here,the illustrated signaling information may be signaling informationrelated to a service.

The part transmitted through the SLT and the MMTP and the parttransmitted through ROUTE may be processed in the UDP and IP layers, andthen encapsulated again in a data link layer. The link layer will bedescribed below. Broadcast data processed in the link layer may bemulticast as a broadcast signal through processes such asencoding/interleaving, etc. in the physical layer.

In this figure, a protocol stack part on a broadband side may betransmitted through HTTP as described above. Data formatted in a DASHsegment form, signaling information, NRT information, etc. may betransmitted through HTTP. Here, the illustrated signaling informationmay be signaling information related to a service. The data may beprocessed through the TCP layer and the IP layer, and then encapsulatedinto the link layer. According to a given embodiment, some or all of theTCP, the IP, and the link layer may be omitted. Broadband data processedthereafter may be transmitted by unicast in the broadband through aprocess for transmission in the physical layer.

Service can be a collection of media components presented to the user inaggregate; components can be of multiple media types; a Service can beeither continuous or intermittent; a Service can be Real Time orNon-Real Time; Real Time Service can consist of a sequence of TVprograms.

FIG. 2 illustrates a relation between the SLT and SLS according to anembodiment of the present invention.

Service signaling provides service discovery and descriptioninformation, and comprises two functional components: Bootstrapsignaling via the Service List Table (SLT) and the Service LayerSignaling (SLS). These represent the information which is necessary todiscover and acquire user services. The SLT enables the receiver tobuild a basic service list, and bootstrap the discovery of the SLS foreach service.

The SLT can enable very rapid acquisition of basic service information.The SLS enables the receiver to discover and access services and theircontent components. Details of the SLT and SLS will be described below.

As described in the foregoing, the SLT may be transmitted throughUDP/IP. In this instance, according to a given embodiment, datacorresponding to the SLT may be delivered through the most robust schemein this transmission.

The SLT may have access information for accessing SLS delivered by theROUTE protocol. In other words, the SLT may be bootstrapped into SLSaccording to the ROUTE protocol. The SLS is signaling informationpositioned in an upper layer of ROUTE in the above-described protocolstack, and may be delivered through ROUTE/UDP/IP. The SLS may betransmitted through one of LCT sessions included in a ROUTE session. Itis possible to access a service component corresponding to a desiredservice using the SLS.

In addition, the SLT may have access information for accessing an MMTsignaling component delivered by MMTP. In other words, the SLT may bebootstrapped into SLS according to the MMTP. The SLS may be delivered byan MMTP signaling message defined in MMT. It is possible to access astreaming service component (MPU) corresponding to a desired serviceusing the SLS. As described in the foregoing, in the present invention,an NRT service component is delivered through the ROUTE protocol, andthe SLS according to the MMTP may include information for accessing theROUTE protocol. In broadband delivery, the SLS is carried overHTTP(S)/TCP/IP.

FIG. 3 illustrates an SLT according to an embodiment of the presentinvention.

First, a description will be given of a relation among respectivelogical entities of service management, delivery, and a physical layer.

Services may be signaled as being one of two basic types. First type isa linear audio/video or audio-only service that may have an app-basedenhancement. Second type is a service whose presentation and compositionis controlled by a downloaded application that is executed uponacquisition of the service. The latter can be called an “app-based”service.

The rules regarding presence of ROUTE/LCT sessions and/or MMTP sessionsfor carrying the content components of a service may be as follows.

For broadcast delivery of a linear service without app-basedenhancement, the service's content components can be carried by either(but not both): (1) one or more ROUTE/LCT sessions, or (2) one or moreMMTP sessions.

For broadcast delivery of a linear service with app-based enhancement,the service's content components can be carried by: (1) one or moreROUTE/LCT sessions, and (2) zero or more MMTP sessions.

In certain embodiments, use of both MMTP and ROUTE for streaming mediacomponents in the same service may not be allowed.

For broadcast delivery of an app-based service, the service's contentcomponents can be carried by one or more ROUTE/LCT sessions.

Each ROUTE session comprises one or more LCT sessions which carry as awhole, or in part, the content components that make up the service. Instreaming services delivery, an LCT session may carry an individualcomponent of a user service such as an audio, video or closed captionstream. Streaming media is formatted as DASH Segments.

Each MMTP session comprises one or more MMTP packet flows which carryMMT signaling messages or as a whole, or in part, the content component.An MMTP packet flow may carry MMT signaling messages or componentsformatted as MPUs.

For the delivery of NRT User Services or system metadata, an LCT sessioncarries file-based content items. These content files may consist ofcontinuous (time-based) or discrete (non-time-based) media components ofan NRT service, or metadata such as Service Signaling or ESG fragments.Delivery of system metadata such as service signaling or ESG fragmentsmay also be achieved through the signaling message mode of MMTP.

A broadcast stream is the abstraction for an RF channel, which isdefined in terms of a carrier frequency centered within a specifiedbandwidth. It is identified by the pair [geographic area, frequency]. Aphysical layer pipe (PLP) corresponds to a portion of the RF channel.Each PLP has certain modulation and coding parameters. It is identifiedby a PLP identifier (PLPID), which is unique within the broadcast streamit belongs to. Here, PLP can be referred to as DP (data pipe).

Each service is identified by two forms of service identifier: a compactform that is used in the SLT and is unique only within the broadcastarea; and a globally unique form that is used in the SLS and the ESG. AROUTE session is identified by a source IP address, destination IPaddress and destination port number. An LCT session (associated with theservice component(s) it carries) is identified by a transport sessionidentifier (TSI) which is unique within the scope of the parent ROUTEsession. Properties common to the LCT sessions, and certain propertiesunique to individual LCT sessions, are given in a ROUTE signalingstructure called a service-based transport session instance description(S-TSID), which is part of the service layer signaling. Each LCT sessionis carried over a single physical layer pipe. According to a givenembodiment, one LCT session may be transmitted through a plurality ofPLPs. Different LCT sessions of a ROUTE session may or may not becontained in different physical layer pipes. Here, the ROUTE session maybe delivered through a plurality of PLPs. The properties described inthe S-TSID include the TSI value and PLPID for each LCT session,descriptors for the delivery objects/files, and application layer FECparameters.

A MMTP session is identified by destination IP address and destinationport number. An MMTP packet flow (associated with the servicecomponent(s) it carries) is identified by a packet_id which is uniquewithin the scope of the parent MMTP session. Properties common to eachMMTP packet flow, and certain properties of MMTP packet flows, are givenin the SLT. Properties for each MMTP session are given by MMT signalingmessages, which may be carried within the MMTP session. Different MMTPpacket flows of a MMTP session may or may not be contained in differentphysical layer pipes. Here, the MMTP session may be delivered through aplurality of PLPs. The properties described in the MMT signalingmessages include the packet_id value and PLPID for each MMTP packetflow. Here, the MMT signaling messages may have a form defined in MMT,or have a deformed form according to embodiments to be described below.

Hereinafter, a description will be given of low level signaling (LLS).

Signaling information which is carried in the payload of IP packets witha well-known address/port dedicated to this function is referred to aslow level signaling (LLS). The IP address and the port number may bedifferently configured depending on embodiments. In one embodiment, LLScan be transported in IP packets with address 224.0.23.60 anddestination port 4937/udp. LLS may be positioned in a portion expressedby “SLT” on the above-described protocol stack. However, according to agiven embodiment, the LLS may be transmitted through a separate physicalchannel (dedicated channel) in a signal frame without being subjected toprocessing of the UDP/IP layer.

UDP/IP packets that deliver LLS data may be formatted in a form referredto as an LLS table. A first byte of each UDP/IP packet that delivers theLLS data may correspond to a start of the LLS table. The maximum lengthof any LLS table is limited by the largest IP packet that can bedelivered from the PHY layer, 65,507 bytes.

The LLS table may include an LLS table ID field that identifies a typeof the LLS table, and an LLS table version field that identifies aversion of the LLS table. According to a value indicated by the LLStable ID field, the LLS table may include the above-described SLT or arating region table (RRT). The RRT may have information about contentadvisory rating.

Hereinafter, the SLT will be described. LLS can be signaling informationwhich supports rapid channel scans and bootstrapping of serviceacquisition by the receiver, and SLT can be a table of signalinginformation which is used to build a basic service listing and providebootstrap discovery of SLS.

The function of the SLT is similar to that of the program associationtable (PAT) in MPEG-2 Systems, and the fast information channel (FIC)found in ATSC Systems. For a receiver first encountering the broadcastemission, this is the place to start. SLT supports a rapid channel scanwhich allows a receiver to build a list of all the services it canreceive, with their channel name, channel number, etc., and SLT providesbootstrap information that allows a receiver to discover the SLS foreach service. For ROUTE/DASH-delivered services, the bootstrapinformation includes the destination IP address and destination port ofthe LCT session that carries the SLS. For MMT/MPU-delivered services,the bootstrap information includes the destination IP address anddestination port of the MMTP session carrying the SLS.

The SLT supports rapid channel scans and service acquisition byincluding the following information about each service in the broadcaststream. First, the SLT can include information necessary to allow thepresentation of a service list that is meaningful to viewers and thatcan support initial service selection via channel number or up/downselection. Second, the SLT can include information necessary to locatethe service layer signaling for each service listed. That is, the SLTmay include access information related to a location at which the SLS isdelivered.

The illustrated SLT according to the present embodiment is expressed asan XML document having an SLT root element. According to a givenembodiment, the SLT may be expressed in a binary format or an XMLdocument.

The SLT root element of the SLT illustrated in the figure may include@bsid, @sltSectionVersion, @sltSectionNumber, @totalSltSectionNumbers,@language, @capabilities, InetSigLoc and/or Service. According to agiven embodiment, the SLT root element may further include @providerId.According to a given embodiment, the SLT root element may not include@language.

The service element may include @serviceId, @SLTserviceSeqNumber,@protected, @majorChannelNo, @minorChannelNo, @serviceCategory,@shortServiceName, @hidden, @slsProtocolType, BroadcastSignaling,@slsPlpId, @slsDestinationIpAddress, @slsDestinationUdpPort,@slsSourceIpAddress, @slsMajorProtocolVersion, @SlsMinorProtocolVersion,@serviceLanguage, @broadbandAccessRequired, @capabilities and/orInetSigLoc.

According to a given embodiment, an attribute or an element of the SLTmay be added/changed/deleted. Each element included in the SLT mayadditionally have a separate attribute or element, and some attribute orelements according to the present embodiment may be omitted. Here, afield which is marked with @ may correspond to an attribute, and a fieldwhich is not marked with @ may correspond to an element.

@bsid is an identifier of the whole broadcast stream. The value of BSIDmay be unique on a regional level.

@providerId can be an index of broadcaster that is using part or all ofthis broadcast stream. This is an optional attribute. When it's notpresent, it means that this broadcast stream is being used by onebroadcaster. @providerId is not illustrated in the figure.

@sltSectionVersion can be a version number of the SLT section. ThesltSectionVersion can be incremented by 1 when a change in theinformation carried within the sit occurs. When it reaches maximumvalue, it wraps around to 0.

@sltSectionNumber can be the number, counting from 1, of this section ofthe SLT. In other words, @sltSectionNumber may correspond to a sectionnumber of the SLT section. When this field is not used,@sltSectionNumber may be set to a default value of 1.

@totalSltSectionNumbers can be the total number of sections (that is,the section with the highest sltSectionNumber) of the SLT of which thissection is part. sltSectionNumber and totalSltSectionNumbers togethercan be considered to indicate “Part M of N” of one portion of the SLTwhen it is sent in fragments. In other words, when the SLT istransmitted, transmission through fragmentation may be supported. Whenthis field is not used, @totalSltSectionNumbers may be set to a defaultvalue of 1. A case in which this field is not used may correspond to acase in which the SLT is not transmitted by being fragmented.

@language can indicate primary language of the services included in thissit instance. According to a given embodiment, a value of this field mayhave a three-character language code defined in the ISO. This field maybe omitted.

@capabilities can indicate required capabilities for decoding andmeaningfully presenting the content for all the services in this sitinstance.

InetSigLoc can provide a URL telling the receiver where it can acquireany requested type of data from external server(s) via broadband. Thiselement may include @urlType as a lower field. According to a value ofthe @urlType field, a type of a URL provided by InetSigLoc may beindicated. According to a given embodiment, when the @urlType field hasa value of 0, InetSigLoc may provide a URL of a signaling server. Whenthe @urlType field has a value of 1, InetSigLoc may provide a URL of anESG server. When the @urlType field has other values, the field may bereserved for future use.

The service field is an element having information about each service,and may correspond to a service entry. Service element fieldscorresponding to the number of services indicated by the SLT may bepresent. Hereinafter, a description will be given of a lowerattribute/element of the service field.

@serviceId can be an integer number that uniquely identify this servicewithin the scope of this broadcast area. According to a givenembodiment, a scope of @serviceId may be changed. @SLTserviceSeqNumbercan be an integer number that indicates the sequence number of the SLTservice information with service ID equal to the serviceId attributeabove. SLTserviceSeqNumber value can start at 0 for each service and canbe incremented by 1 every time any attribute in this service element ischanged. If no attribute values are changed compared to the previousService element with a particular value of ServiceID thenSLTserviceSeqNumber would not be incremented. The SLTserviceSeqNumberfield wraps back to 0 after reaching the maximum value.

@protected is flag information which may indicate whether one or morecomponents for significant reproduction of the service are in aprotected state. When set to “1” (true), that one or more componentsnecessary for meaningful presentation is protected. When set to “0”(false), this flag indicates that no components necessary for meaningfulpresentation of the service are protected. Default value is false.

@majorChannelNo is an integer number representing the “major” channelnumber of the service. An example of the field may have a range of 1 to999.

@minorChannelNo is an integer number representing the “minor” channelnumber of the service. An example of the field may have a range of 1 to999.

@serviceCategory can indicate the category of this service. This fieldmay indicate a type that varies depending on embodiments. According to agiven embodiment, when this field has values of 1, 2, and 3, the valuesmay correspond to a linear A/V service, a linear audio only service, andan app-based service, respectively. When this field has a value of 0,the value may correspond to a service of an undefined category. Whenthis field has other values except for 1, 2, and 3, the field may bereserved for future use. @shortServiceName can be a short string name ofthe Service.

@hidden can be boolean value that when present and set to “true”indicates that the service is intended for testing or proprietary use,and is not to be selected by ordinary TV receivers. The default value is“false” when not present.

@slsProtocolType can be an attribute indicating the type of protocol ofService Layer Signaling used by this service. This field may indicate atype that varies depending on embodiments. According to a givenembodiment, when this field has values of 1 and 2, protocols of SLS usedby respective corresponding services may be ROUTE and MMTP,respectively. When this field has other values except for 0, the fieldmay be reserved for future use. This field may be referred to as@slsProtocol.

BroadcastSignaling and lower attributes/elements thereof may provideinformation related to broadcast signaling. When the BroadcastSignalingelement is not present, the child element InetSigLoc of the parentservice element can be present and its attribute urlType includesURL_type 0x00 (URL to signaling server). In this case attribute urlsupports the query parameter svc=<service_id> where service_idcorresponds to the serviceId attribute for the parent service element.

Alternatively when the BroadcastSignaling element is not present, theelement InetSigLoc can be present as a child element of the sit rootelement and the attribute urlType of that InetSigLoc element includesURL_type 0x00 (URL to signaling server). In this case, attribute url forURL_type 0x00 supports the query parameter svc=<service_id> whereservice_id corresponds to the serviceId attribute for the parent Serviceelement.

@slsPlpId can be a string representing an integer number indicating thePLP ID of the physical layer pipe carrying the SLS for this service.

@slsDestinationIpAddress can be a string containing the dotted-IPv4destination address of the packets carrying SLS data for this service.

@slsDestinationUdpPort can be a string containing the port number of thepackets carrying SLS data for this service. As described in theforegoing, SLS bootstrapping may be performed by destination IP/UDPinformation.

@slsSourceIpAddress can be a string containing the dotted-IPv4 sourceaddress of the packets carrying SLS data for this service.

@slsMajorProtocolVersion can be major version number of the protocolused to deliver the service layer signaling for this service. Defaultvalue is 1.

@SlsMinorProtocolVersion can be minor version number of the protocolused to deliver the service layer signaling for this service. Defaultvalue is 0.

@serviceLanguage can be a three-character language code indicating theprimary language of the service. A value of this field may have a formthat varies depending on embodiments.

@broadbandAccessRequired can be a Boolean indicating that broadbandaccess is required for a receiver to make a meaningful presentation ofthe service. Default value is false. When this field has a value ofTrue, the receiver needs to access a broadband for significant servicereproduction, which may correspond to a case of hybrid service delivery.

@capabilities can represent required capabilities for decoding andmeaningfully presenting the content for the service with service IDequal to the service Id attribute above.

InetSigLoc can provide a URL for access to signaling or announcementinformation via broadband, if available. Its data type can be anextension of the any URL data type, adding an @urlType attribute thatindicates what the URL gives access to. An @urlType field of this fieldmay indicate the same meaning as that of the @urlType field ofInetSigLoc described above. When an InetSigLoc element of attributeURL_type 0x00 is present as an element of the SLT, it can be used tomake HTTP requests for signaling metadata. The HTTP POST message bodymay include a service term. When the InetSigLoc element appears at thesection level, the service term is used to indicate the service to whichthe requested signaling metadata objects apply. If the service term isnot present, then the signaling metadata objects for all services in thesection are requested. When the InetSigLoc appears at the service level,then no service term is needed to designate the desired service. When anInetSigLoc element of attribute URL_type 0x01 is provided, it can beused to retrieve ESG data via broadband. If the element appears as achild element of the service element, then the URL can be used toretrieve ESG data for that service. If the element appears as a childelement of the SLT element, then the URL can be used to retrieve ESGdata for all services in that section.

In another example of the SLT, @sltSectionVersion, @sltSectionNumber,@totalSltSectionNumbers and/or @language fields of the SLT may beomitted

In addition, the above-described InetSigLoc field may be replaced by@sltInetSigUri and/or @sltInetEsgUri field. The two fields may includethe URI of the signaling server and URI information of the ESG server,respectively. The InetSigLoc field corresponding to a lower field of theSLT and the InetSigLoc field corresponding to a lower field of theservice field may be replaced in a similar manner.

The suggested default values may vary depending on embodiments. Anillustrated “use” column relates to the respective fields. Here, “1” mayindicate that a corresponding field is an essential field, and “0 . . .1” may indicate that a corresponding field is an optional field.

FIG. 4 illustrates SLS bootstrapping and a service discovery processaccording to an embodiment of the present invention.

Hereinafter, SLS will be described.

SLS can be signaling which provides information for discovery andacquisition of services and their content components.

For ROUTE/DASH, the SLS for each service describes characteristics ofthe service, such as a list of its components and where to acquire them,and the receiver capabilities required to make a meaningful presentationof the service. In the ROUTE/DASH system, the SLS includes the userservice bundle description (USBD), the S-TSID and the DASH mediapresentation description (MPD). Here, USBD or user service description(USD) is one of SLS XML fragments, and may function as a signaling herbthat describes specific descriptive information. USBD/USD may beextended beyond 3GPP MBMS. Details of USBD/USD will be described below.

The service signaling focuses on basic attributes of the service itself,especially those attributes needed to acquire the service. Properties ofthe service and programming that are intended for viewers appear asservice announcement, or ESG data.

Having separate Service Signaling for each service permits a receiver toacquire the appropriate SLS for a service of interest without the needto parse the entire SLS carried within a broadcast stream.

For optional broadband delivery of Service Signaling, the SLT caninclude HTTP URLs where the Service Signaling files can be obtained, asdescribed above.

LLS is used for bootstrapping SLS acquisition, and subsequently, the SLSis used to acquire service components delivered on either ROUTE sessionsor MMTP sessions. The described figure illustrates the followingsignaling sequences. Receiver starts acquiring the SLT described above.Each service identified by service_id delivered over ROUTE sessionsprovides SLS bootstrapping information: PLPID(#1), source IP address(sIP1), destination IP address (dIP1), and destination port number(dPort1). Each service identified by service_id delivered over MMTPsessions provides SLS bootstrapping information: PLPID(#2), destinationIP address (dIP2), and destination port number (dPort2).

For streaming services delivery using ROUTE, the receiver can acquireSLS fragments carried over the IP/UDP/LCT session and PLP; whereas forstreaming services delivery using MMTP, the receiver can acquire SLSfragments carried over an MMTP session and PLP. For service deliveryusing ROUTE, these SLS fragments include USBD/USD fragments, S-TSIDfragments, and MPD fragments. They are relevant to one service. USBD/USDfragments describe service layer properties and provide URI referencesto S-TSID fragments and URI references to MPD fragments. In other words,the USBD/USD may refer to S-TSID and MPD. For service delivery usingMMTP, the USBD references the MMT signaling's MPT message, the MP Tableof which provides identification of package ID and location informationfor assets belonging to the service. Here, an asset is a multimedia dataentity, and may refer to a data entity which is combined into one uniqueID and is used to generate one multimedia presentation. The asset maycorrespond to a service component included in one service. The MPTmessage is a message having the MP table of MMT. Here, the MP table maybe an MMT package table having information about content and an MMTasset. Details may be similar to a definition in MMT. Here, mediapresentation may correspond to a collection of data that establishesbounded/unbounded presentation of media content.

The S-TSID fragment provides component acquisition informationassociated with one service and mapping between DASH Representationsfound in the MPD and in the TSI corresponding to the component of theservice. The S-TSID can provide component acquisition information in theform of a TSI and the associated DASH representation identifier, andPLPID carrying DASH segments associated with the DASH representation. Bythe PLPID and TSI values, the receiver collects the audio/videocomponents from the service and begins buffering DASH media segmentsthen applies the appropriate decoding processes.

For USBD listing service components delivered on MMTP sessions, asillustrated by “Service #2” in the described figure, the receiver alsoacquires an MPT message with matching MMT_package_id to complete theSLS. An MPT message provides the full list of service componentscomprising a service and the acquisition information for each component.Component acquisition information includes MMTP session information, thePLPID carrying the session and the packet_id within that session.

According to a given embodiment, for example, in ROUTE, two or moreS-TSID fragments may be used. Each fragment may provide accessinformation related to LCT sessions delivering content of each service.

In ROUTE, S-TSID, USBD/USD, MPD, or an LCT session delivering S-TSID,USBD/USD or MPD may be referred to as a service signaling channel. InMMTP, USBD/UD, an MMT signaling message, or a packet flow delivering theMMTP or USBD/UD may be referred to as a service signaling channel.

Unlike the illustrated example, one ROUTE or MMTP session may bedelivered through a plurality of PLPs. In other words, one service maybe delivered through one or more PLPs. As described in the foregoing,one LCT session may be delivered through one PLP. Unlike the figure,according to a given embodiment, components included in one service maybe delivered through different ROUTE sessions. In addition, according toa given embodiment, components included in one service may be deliveredthrough different MMTP sessions. According to a given embodiment,components included in one service may be delivered separately through aROUTE session and an MMTP session. Although not illustrated, componentsincluded in one service may be delivered via broadband (hybriddelivery).

FIG. 5 illustrates a USBD fragment for ROUTE/DASH according to anembodiment of the present invention.

Hereinafter, a description will be given of SLS in delivery based onROUTE.

SLS provides detailed technical information to the receiver to enablethe discovery and access of services and their content components. Itcan include a set of XML-encoded metadata fragments carried over adedicated LCT session. That LCT session can be acquired using thebootstrap information contained in the SLT as described above. The SLSis defined on a per-service level, and it describes the characteristicsand access information of the service, such as a list of its contentcomponents and how to acquire them, and the receiver capabilitiesrequired to make a meaningful presentation of the service. In theROUTE/DASH system, for linear services delivery, the SLS consists of thefollowing metadata fragments: USBD, S-TSID and the DASH MPD. The SLSfragments can be delivered on a dedicated LCT transport session withTSI=0. According to a given embodiment, a TSI of a particular LCTsession (dedicated LCT session) in which an SLS fragment is deliveredmay have a different value. According to a given embodiment, an LCTsession in which an SLS fragment is delivered may be signaled using theSLT or another scheme.

ROUTE/DASH SLS can include the user service bundle description (USBD)and service-based transport session instance description (S-TSID)metadata fragments. These service signaling fragments are applicable toboth linear and application-based services. The USBD fragment containsservice identification, device capabilities information, references toother SLS fragments required to access the service and constituent mediacomponents, and metadata to enable the receiver to determine thetransport mode (broadcast and/or broadband) of service components. TheS-TSID fragment, referenced by the USBD, provides transport sessiondescriptions for the one or more ROUTE/LCT sessions in which the mediacontent components of a service are delivered, and descriptions of thedelivery objects carried in those LCT sessions. The USBD and S-TSID willbe described below.

In streaming content signaling in ROUTE-based delivery, a streamingcontent signaling component of SLS corresponds to an MPD fragment. TheMPD is typically associated with linear services for the delivery ofDASH Segments as streaming content. The MPD provides the resourceidentifiers for individual media components of the linear/streamingservice in the form of Segment URLs, and the context of the identifiedresources within the Media Presentation. Details of the MPD will bedescribed below.

In app-based enhancement signaling in ROUTE-based delivery, app-basedenhancement signaling pertains to the delivery of app-based enhancementcomponents, such as an application logic file, locally-cached mediafiles, network content items, or a notification stream. An applicationcan also retrieve locally-cached data over a broadband connection whenavailable.

Hereinafter, a description will be given of details of USBD/USDillustrated in the figure.

The top level or entry point SLS fragment is the USBD fragment. Anillustrated USBD fragment is an example of the present invention, basicfields of the USBD fragment not illustrated in the figure may beadditionally provided according to a given embodiment. As described inthe foregoing, the illustrated USBD fragment has an extended form, andmay have fields added to a basic configuration.

The illustrated USBD may have a bundleDescription root element. ThebundleDescription root element may have a userServiceDescriptionelement. The userServiceDescription element may correspond to aninstance for one service.

The userServiceDescription element may include @serviceId,@atsc:serviceId, @atsc:serviceStatus, @atsc:fullMPDUri, @atsc:sTSIDUri,name, serviceLanguage, atsc:capabilityCode and/or deliveryMethod.

@serviceId can be a globally unique URI that identifies a service,unique within the scope of the BSID. This parameter can be used to linkto ESG data (Service@globalServiceID).

@atsc:serviceId is a reference to corresponding service entry inLLS(SLT). The value of this attribute is the same value of serviceIdassigned to the entry.

@atsc:serviceStatus can specify the status of this service. The valueindicates whether this service is active or inactive. When set to “I”(true), that indicates service is active. When this field is not used,@atsc:serviceStatus may be set to a default value of 1.

@atsc:fullMPDUri can reference an MPD fragment which containsdescriptions for contents components of the service delivered overbroadcast and optionally, also over broadband.

@atsc:sTSIDUri can reference the S-TSID fragment which provides accessrelated parameters to the Transport sessions carrying contents of thisservice.

name can indicate name of the service as given by the lang attribute,name element can include lang attribute, which indicating language ofthe service name. The language can be specified according to XML datatypes.

serviceLanguage can represent available languages of the service. Thelanguage can be specified according to XML data types.

atsc:capabilityCode can specify the capabilities required in thereceiver to be able to create a meaningful presentation of the contentof this service. According to a given embodiment, this field may specifya predefined capability group. Here, the capability group may be a groupof capability attribute values for significant presentation. This fieldmay be omitted according to a given embodiment.

deliveryMethod can be a container of transport related informationpertaining to the contents of the service over broadcast and(optionally) broadband modes of access. Referring to data included inthe service, when the number of the data is N, delivery schemes forrespective data may be described by this element. The deliveryMethod mayinclude an r12:broadcastAppService element and an r12:unicastAppServiceelement. Each lower element may include a basePattern element as a lowerelement.

r12:broadcastAppService can be a DASH Representation delivered overbroadcast, in multiplexed or non-multiplexed form, containing thecorresponding media component(s) belonging to the service, across allPeriods of the affiliated media presentation. In other words, each ofthe fields may indicate DASH representation delivered through thebroadcast network.

r12:unicastAppService can be a DASH Representation delivered overbroadband, in multiplexed or non-multiplexed form, containing theconstituent media content component(s) belonging to the service, acrossall periods of the affiliated media presentation. In other words, eachof the fields may indicate DASH representation delivered via broadband.

basePattern can be a character pattern for use by the receiver to matchagainst any portion of the segment URL used by the DASH client torequest media segments of a parent representation under its containingperiod. A match implies that the corresponding requested media segmentis carried over broadcast transport. In a URL address for receiving DASHrepresentation expressed by each of the r12:broadcastAppService elementand the r12:unicastAppService element, a part of the URL, etc. may havea particular pattern. The pattern may be described by this field. Somedata may be distinguished using this information. The proposed defaultvalues may vary depending on embodiments. The “use” column illustratedin the figure relates to each field. Here, M may denote an essentialfield, O may denote an optional field, OD may denote an optional fieldhaving a default value, and CM may denote a conditional essential field.0 . . . 1 to 0 . . . N may indicate the number of available fields.

FIG. 6 illustrates an S-TSID fragment for ROUTE/DASH according to anembodiment of the present invention.

Hereinafter, a description will be given of the S-TSID illustrated inthe figure in detail.

S-TSID can be an SLS XML fragment which provides the overall sessiondescription information for transport session(s) which carry the contentcomponents of a service. The S-TSID is the SLS metadata fragment thatcontains the overall transport session description information for thezero or more ROUTE sessions and constituent LCT sessions in which themedia content components of a service are delivered. The S-TSID alsoincludes file metadata for the delivery object or object flow carried inthe LCT sessions of the service, as well as additional information onthe payload formats and content components carried in those LCTsessions.

Each instance of the S-TSID fragment is referenced in the USBD fragmentby the @atsc:sTSIDUri attribute of the userServiceDescription element.The illustrated S-TSID according to the present embodiment is expressedas an XML document. According to a given embodiment, the S-TSID may beexpressed in a binary format or as an XML document.

The illustrated S-TSID may have an S-TSID root element. The S-TSID rootelement may include @serviceId and/or RS.

@serviceID can be a reference corresponding service element in the USD.The value of this attribute can reference a service with a correspondingvalue of service_id.

The RS element may have information about a ROUTE session for deliveringthe service data. Service data or service components may be deliveredthrough a plurality of ROUTE sessions, and thus the number of RSelements may be 1 to N.

The RS element may include @bsid, @sIpAddr, @dIpAddr, @dport, @PLPIDand/or LS.

@bsid can be an identifier of the broadcast stream within which thecontent component(s) of the broadcastAppService are carried. When thisattribute is absent, the default broadcast stream is the one whose PLPscarry SLS fragments for this service. Its value can be identical to thatof the broadcast_stream_id in the SLT.

@sIpAddr can indicate source IP address. Here, the source IP address maybe a source IP address of a ROUTE session for delivering a servicecomponent included in the service. As described in the foregoing,service components of one service may be delivered through a pluralityof ROUTE sessions. Thus, the service components may be transmitted usinganother ROUTE session other than the ROUTE session for delivering theS-TSID. Therefore, this field may be used to indicate the source IPaddress of the ROUTE session. A default value of this field may be asource IP address of a current ROUTE session. When a service componentis delivered through another ROUTE session, and thus the ROUTE sessionneeds to be indicated, a value of this field may be a value of a sourceIP address of the ROUTE session. In this case, this field may correspondto M, that is, an essential field.

@dIpAddr can indicate destination IP address. Here, a destination IPaddress may be a destination IP address of a ROUTE session that deliversa service component included in a service. For a similar case to theabove description of @sIpAddr, this field may indicate a destination IPaddress of a ROUTE session that delivers a service component. A defaultvalue of this field may be a destination IP address of a current ROUTEsession. When a service component is delivered through another ROUTEsession, and thus the ROUTE session needs to be indicated, a value ofthis field may be a value of a destination IP address of the ROUTEsession. In this case, this field may correspond to M, that is, anessential field.

@dport can indicate destination port. Here, a destination port may be adestination port of a ROUTE session that delivers a service componentincluded in a service. For a similar case to the above description of@sIpAddr, this field may indicate a destination port of a ROUTE sessionthat delivers a service component. A default value of this field may bea destination port number of a current ROUTE session. When a servicecomponent is delivered through another ROUTE session, and thus the ROUTEsession needs to be indicated, a value of this field may be adestination port number value of the ROUTE session. In this case, thisfield may correspond to M, that is, an essential field.

@PLPID may be an ID of a PLP for a ROUTE session expressed by an RS. Adefault value may be an ID of a PLP of an LCT session including acurrent S-TSID. According to a given embodiment, this field may have anID value of a PLP for an LCT session for delivering an S-TSID in theROUTE session, and may have ID values of all PLPs for the ROUTE session.

An LS element may have information about an LCT session for delivering aservice data. Service data or service components may be deliveredthrough a plurality of LCT sessions, and thus the number of LS elementsmay be 1 to N.

The LS element may include @tsi, @PLPID, @bw, @startTime, @endTime,SrcFlow and/or RprFlow.

@tsi may indicate a TSI value of an LCT session for delivering a servicecomponent of a service.

@PLPID may have ID information of a PLP for the LCT session. This valuemay be overwritten on a basic ROUTE session value.

@bw may indicate a maximum bandwidth value. @startTime may indicate astart time of the LCT session. @endTime may indicate an end time of theLCT session. A SrcFlow element may describe a source flow of ROUTE. ARprFlow element may describe a repair flow of ROUTE.

The proposed default values may be varied according to an embodiment.The “use” column illustrated in the figure relates to each field. Here,M may denote an essential field, O may denote an optional field, OD maydenote an optional field having a default value, and CM may denote aconditional essential field. 0 . . . 1 to 0 . . . N may indicate thenumber of available fields.

Hereinafter, a description will be given of MPD for ROUTE/DASH.

The MPD is an SLS metadata fragment which contains a formalizeddescription of a DASH Media Presentation, corresponding to a linearservice of a given duration defined by the broadcaster (for example asingle TV program, or the set of contiguous linear TV programs over aperiod of time). The contents of the MPD provide the resourceidentifiers for Segments and the context for the identified resourceswithin the Media Presentation. The data structure and semantics of theMPD fragment can be according to the MPD defined by MPEG DASH.

One or more of the DASH Representations conveyed in the MPD can becarried over broadcast. The MPD may describe additional Representationsdelivered over broadband, e.g. in the case of a hybrid service, or tosupport service continuity in handoff from broadcast to broadcast due tobroadcast signal degradation (e.g. driving through a tunnel).

FIG. 7 illustrates a USBD/USD fragment for MMT according to anembodiment of the present invention.

MMT SLS for linear services comprises the USBD fragment and the MMTPackage (MP) table. The MP table is as described above. The USBDfragment contains service identification, device capabilitiesinformation, references to other SLS information required to access theservice and constituent media components, and the metadata to enable thereceiver to determine the transport mode (broadcast and/or broadband) ofthe service components. The MP table for MPU components, referenced bythe USBD, provides transport session descriptions for the MMTP sessionsin which the media content components of a service are delivered and thedescriptions of the Assets carried in those MMTP sessions.

The streaming content signaling component of the SLS for MPU componentscorresponds to the MP table defined in MMT. The MP table provides a listof MMT assets where each asset corresponds to a single service componentand the description of the location information for this component.

USBD fragments may also contain references to the S-TSID and the MPD asdescribed above, for service components delivered by the ROUTE protocoland the broadband, respectively. According to a given embodiment, indelivery through MMT, a service component delivered through the ROUTEprotocol is NRT data, etc. Thus, in this case, MPD may be unnecessary.In addition, in delivery through MMT, information about an LCT sessionfor delivering a service component, which is delivered via broadband, isunnecessary, and thus an S-TSID may be unnecessary. Here, an MMT packagemay be a logical collection of media data delivered using MMT. Here, anMMTP packet may refer to a formatted unit of media data delivered usingMMT. An MPU may refer to a generic container of independently decodabletimed/non-timed data. Here, data in the MPU is media codec agnostic.

Hereinafter, a description will be given of details of the USBD/USDillustrated in the figure.

The illustrated USBD fragment is an example of the present invention,and basic fields of the USBD fragment may be additionally providedaccording to an embodiment. As described in the foregoing, theillustrated USBD fragment has an extended form, and may have fieldsadded to a basic structure.

The illustrated USBD according to an embodiment of the present inventionis expressed as an XML document. According to a given embodiment, theUSBD may be expressed in a binary format or as an XML document.

The illustrated USBD may have a bundleDescription root element. ThebundleDescription root element may have a userServiceDescriptionelement. The userServiceDescription element may be an instance for oneservice.

The userServiceDescription element may include @serviceId,@atsc:serviceId, name, serviceLanguage, atsc:capabilityCode,atsc:Channel, atsc:mpuComponent, atsc:routeComponent,atsc:broadbandComponent and/or atsc:ComponentInfo.

Here, @serviceId, @atsc:serviceId, name, serviceLanguage, andatsc:capabilityCode may be as described above. The lang field below thename field may be as described above. atsc:capabilityCode may be omittedaccording to a given embodiment.

The userServiceDescription element may further include anatsc:contentAdvisoryRating element according to an embodiment. Thiselement may be an optional element. atsc:contentAdvisoryRating canspecify the content advisory rating. This field is not illustrated inthe figure.

atsc:Channel may have information about a channel of a service. Theatsc:Channel element may include @atsc:majorChannelNo,@atsc:minorChannelNo, @atsc:serviceLang, @atsc:serviceGenre,@atsc:serviceIcon and/or atsc:ServiceDescription. @atsc:majorChannelNo,@atsc:minorChannelNo, and @atsc:serviceLang may be omitted according toa given embodiment.

@atsc:majorChannelNo is an attribute that indicates the major channelnumber of the service.

@atsc:minorChannelNo is an attribute that indicates the minor channelnumber of the service.

@atsc:serviceLang is an attribute that indicates the primary languageused in the service.

@atsc:serviceGenre is an attribute that indicates primary genre of theservice.

@atsc:serviceIcon is an attribute that indicates the Uniform ResourceLocator (URL) for the icon used to represent this service.

atsc:ServiceDescription includes service description, possibly inmultiple languages. atsc:ServiceDescription includes can include@atsc:serviceDescrText and/or @atsc:serviceDescrLang.

@atsc:serviceDescrText is an attribute that indicates description of theservice.

@atsc:serviceDescrLang is an attribute that indicates the language ofthe serviceDescrText attribute above.

atsc:mpuComponent may have information about a content component of aservice delivered in a form of an MPU. atsc:mpuComponent may include@atsc:mmtPackageId and/or @atsc:nextMmtPackageId.

@atsc:mmtPackageId can reference a MMT Package for content components ofthe service delivered as MPUs.

@atsc:nextMmtPackageId can reference a MMT Package to be used after theone referenced by @atsc:mmtPackageId in time for content components ofthe service delivered as MPUs.

atsc:routeComponent may have information about a content component of aservice delivered through ROUTE. atsc:routeComponent may include@atsc:sTSIDUri, @sTSIDPIpId, @sTSIDDestinationIpAddress,@sTSIDDestinationUdpPort, @sTSIDSourceIpAddress, @sTSIDMajorProtocolVersion and/or @sTSIDMinorProtocolVersion.

@atsc:sTSIDUri can be a reference to the S-TSID fragment which providesaccess related parameters to the Transport sessions carrying contents ofthis service. This field may be the same as a URI for referring to anS-TSID in USBD for ROUTE described above. As described in the foregoing,in service delivery by the MMTP, service components, which are deliveredthrough NRT, etc., may be delivered by ROUTE. This field may be used torefer to the S-TSID therefor.

@sTSIDPIpId can be a string representing an integer number indicatingthe PLP ID of the physical layer pipe carrying the S-TSID for thisservice. (default: current physical layer pipe).

@sTSIDDestinationIpAddress can be a string containing the dotted-IPv4destination address of the packets carrying S-TSID for this service.(default: current MMTP session's source IP address)

@sTSIDDestinationUdpPort can be a string containing the port number ofthe packets carrying S-TSID for this service.

@sTSIDSourceIpAddress can be a string containing the dotted-IPv4 sourceaddress of the packets carrying S-TSID for this service.

@sTSIDMajorProtocolVersion can indicate major version number of theprotocol used to deliver the S-TSID for this service. Default value is1.

@sTSIDMinorProtocolVersion can indicate minor version number of theprotocol used to deliver the S-TSID for this service. Default value is0.

atsc:broadbandComponent may have information about a content componentof a service delivered via broadband. In other words,atsc:broadbandComponent may be a field on the assumption of hybriddelivery. atsc:broadbandComponent may further include @atsc:fullfMPDUri.

@atsc:fullfMPDUri can be a reference to an MPD fragment which containsdescriptions for contents components of the service delivered overbroadband.

An atsc:ComponentInfo field may have information about an availablecomponent of a service. The atsc:ComponentInfo field may haveinformation about a type, a role, a name, etc. of each component. Thenumber of atsc:ComponentInfo fields may correspond to the number (N) ofrespective components. The atsc:ComponentInfo field may include@atsc:componentType, @atsc:componentRole, @atsc:componentProtectedFlag,@atsc:componentId and/or @atsc:componentName.

@atsc:componentType is an attribute that indicates the type of thiscomponent. Value of 0 indicates an audio component. Value of 1 indicatesa video component. Value of 2 indicated a closed caption component.Value of 3 indicates an application component. Values 4 to 7 arereserved. A meaning of a value of this field may be differently setdepending on embodiments.

@atsc:componentRole is an attribute that indicates the role or kind ofthis component.

For audio (when componentType attribute above is equal to 0): values ofcomponentRole attribute are as follows: 0=Complete main, I=Music andEffects, 2=Dialog, 3=Commentary, 4=Visually Impaired, 5=HearingImpaired, 6=Voice-Over, 7-254=reserved, 255=unknown.

For video (when componentType attribute above is equal to 1) values ofcomponentRole attribute are as follows: 0=Primary video, 1=Alternativecamera view, 2=Other alternative video component, 3=Sign language inset,4=Follow subject video, 5=3D video left view, 6=3D video right view,7=3D video depth information, 8=Part of video array <x,y> of <n,m>,9=Follow-Subject metadata, 10-254=reserved, 255=unknown.

For Closed Caption component (when componentType attribute above isequal to 2) values of componentRole attribute are as follows: 0=Normal,1=Easy reader, 2-254=reserved, 255=unknown.

When componentType attribute above is between 3 to 7, inclusive, thecomponentRole can be equal to 255. A meaning of a value of this fieldmay be differently set depending on embodiments.

@atsc:componentProtectedFlag is an attribute that indicates if thiscomponent is protected (e.g. encrypted). When this flag is set to avalue of 1 this component is protected (e.g. encrypted). When this flagis set to a value of 0 this component is not protected (e.g. encrypted).When not present the value of componentProtectedFlag attribute isinferred to be equal to 0. A meaning of a value of this field may bedifferently set depending on embodiments.

@atsc:componentId is an attribute that indicates the identifier of thiscomponent. The value of this attribute can be the same as the asset_idin the MP table corresponding to this component.

@atsc:componentName is an attribute that indicates the human readablename of this component.

The proposed default values may vary depending on embodiments. The “use”column illustrated in the figure relates to each field. Here, M maydenote an essential field, O may denote an optional field, OD may denotean optional field having a default value, and CM may denote aconditional essential field. 0 . . . 1 to 0 . . . N may indicate thenumber of available fields.

Hereinafter, a description will be given of MPD for MMT.

The Media Presentation Description is an SLS metadata fragmentcorresponding to a linear service of a given duration defined by thebroadcaster (for example a single TV program, or the set of contiguouslinear TV programs over a period of time). The contents of the MPDprovide the resource identifiers for segments and the context for theidentified resources within the media presentation. The data structureand semantics of the MPD can be according to the MPD defined by MPEGDASH.

In the present embodiment, an MPD delivered by an MMTP session describesRepresentations delivered over broadband, e.g. in the case of a hybridservice, or to support service continuity in handoff from broadcast tobroadband due to broadcast signal degradation (e.g. driving under amountain or through a tunnel).

Hereinafter, a description will be given of an MMT signaling message forMMT.

When MMTP sessions are used to carry a streaming service, MMT signalingmessages defined by MMT are delivered by MMTP packets according tosignaling message mode defined by MMT. The value of the packet_id fieldof MMTP packets carrying service layer signaling is set to ‘00’ exceptfor MMTP packets carrying MMT signaling messages specific to an asset,which can be set to the same packet_id value as the MMTP packetscarrying the asset. Identifiers referencing the appropriate package foreach service are signaled by the USBD fragment as described above. MMTPackage Table (MPT) messages with matching MMT_package_id can bedelivered on the MMTP session signaled in the SLT. Each MMTP sessioncarries MMT signaling messages specific to its session or each assetdelivered by the MMTP session.

In other words, it is possible to access USBD of the MMTP session byspecifying an IP destination address/port number, etc. of a packethaving the SLS for a particular service in the SLT. As described in theforegoing, a packet ID of an MMTP packet carrying the SLS may bedesignated as a particular value such as 00, etc. It is possible toaccess an MPT message having a matched packet ID using theabove-described package IP information of USBD. As described below, theMPT message may be used to access each service component/asset.

The following MMTP messages can be delivered by the MMTP sessionsignaled in the SLT.

MMT Package Table (MPT) message: This message carries an MP (MMTPackage) table which contains the list of all Assets and their locationinformation as defined by MMT. If an Asset is delivered by a PLPdifferent from the current PLP delivering the MP table, the identifierof the PLP carrying the asset can be provided in the MP table usingphysical layer pipe identifier descriptor. The physical layer pipeidentifier descriptor will be described below.

MMT ATSC3 (MA3) message mmt_atsc3_message( ): This message carriessystem metadata specific for services including service layer signalingas described above. mmt_atsc3_message( ) will be described below.

The following MMTP messages can be delivered by the MMTP sessionsignaled in the SLT, if required.

Media Presentation Information (MPI) message: This message carries anMPI table which contains the whole document or a subset of a document ofpresentation information. An MP table associated with the MPI table alsocan be delivered by this message.

Clock Relation Information (CRI) message: This message carries a CRItable which contains clock related information for the mapping betweenthe NTP timestamp and the MPEG-2 STC. According to a given embodiment,the CRI message may not be delivered through the MMTP session.

The following MMTP messages can be delivered by each MMTP sessioncarrying streaming content.

Hypothetical Receiver Buffer Model message: This message carriesinformation required by the receiver to manage its buffer.

Hypothetical Receiver Buffer Model Removal message: This message carriesinformation required by the receiver to manage its MMT de-capsulationbuffer.

Hereinafter, a description will be given of mmt_atsc3_message( )corresponding to one of MMT signaling messages. An MMT Signaling messagemmt_atsc3_message( ) is defined to deliver information specific toservices according to the present invention described above. Thesignaling message may include message ID, version, and/or length fieldscorresponding to basic fields of the MMT signaling message. A payload ofthe signaling message may include service ID information, content typeinformation, content version information, content compressioninformation and/or URI information. The content type information mayindicate a type of data included in the payload of the signalingmessage. The content version information may indicate a version of dataincluded in the payload, and the content compression information mayindicate a type of compression applied to the data. The URI informationmay have URI information related to content delivered by the message.

Hereinafter, a description will be given of the physical layer pipeidentifier descriptor.

The physical layer pipe identifier descriptor is a descriptor that canbe used as one of descriptors of the MP table described above. Thephysical layer pipe identifier descriptor provides information about thePLP carrying an asset. If an asset is delivered by a PLP different fromthe current PLP delivering the MP table, the physical layer pipeidentifier descriptor can be used as an asset descriptor in theassociated MP table to identify the PLP carrying the asset. The physicallayer pipe identifier descriptor may further include BSID information inaddition to PLP ID information. The BSID may be an ID of a broadcaststream that delivers an MMTP packet for an asset described by thedescriptor.

FIG. 8 illustrates a link layer protocol architecture according to anembodiment of the present invention.

Hereinafter, a link layer will be described.

The link layer is the layer between the physical layer and the networklayer, and transports the data from the network layer to the physicallayer at the sending side and transports the data from the physicallayer to the network layer at the receiving side. The purpose of thelink layer includes abstracting all input packet types into a singleformat for processing by the physical layer, ensuring flexibility andfuture extensibility for as yet undefined input types. In addition,processing within the link layer ensures that the input data can betransmitted in an efficient manner, for example by providing options tocompress redundant information in the headers of input packets. Theoperations of encapsulation, compression and so on are referred to asthe link layer protocol and packets created using this protocol arecalled link layer packets. The link layer may perform functions such aspacket encapsulation, overhead reduction and/or signaling transmission,etc.

Hereinafter, packet encapsulation will be described. Link layer protocolallows encapsulation of any type of packet, including ones such as IPpackets and MPEG-2 TS. Using link layer protocol, the physical layerneed only process one single packet format, independent of the networklayer protocol type (here we consider MPEG-2 TS packet as a kind ofnetwork layer packet.) Each network layer packet or input packet istransformed into the payload of a generic link layer packet.Additionally, concatenation and segmentation can be performed in orderto use the physical layer resources efficiently when the input packetsizes are particularly small or large.

As described in the foregoing, segmentation may be used in packetencapsulation. When the network layer packet is too large to processeasily in the physical layer, the network layer packet is divided intotwo or more segments. The link layer packet header includes protocolfields to perform segmentation on the sending side and reassembly on thereceiving side. When the network layer packet is segmented, each segmentcan be encapsulated to link layer packet in the same order as originalposition in the network layer packet. Also each link layer packet whichincludes a segment of network layer packet can be transported to PHYlayer consequently.

As described in the foregoing, concatenation may be used in packetencapsulation. When the network layer packet is small enough for thepayload of a link layer packet to include several network layer packets,the link layer packet header includes protocol fields to performconcatenation. The concatenation is combining of multiple small sizednetwork layer packets into one payload. When the network layer packetsare concatenated, each network layer packet can be concatenated topayload of link layer packet in the same order as original input order.Also each packet which constructs a payload of link layer packet can bewhole packet, not a segment of packet.

Hereinafter, overhead reduction will be described. Use of the link layerprotocol can result in significant reduction in overhead for transportof data on the physical layer. The link layer protocol according to thepresent invention may provide IP overhead reduction and/or MPEG-2 TSoverhead reduction. In IP overhead reduction, IP packets have a fixedheader format, however some of the information which is needed in acommunication environment may be redundant in a broadcast environment.Link layer protocol provides mechanisms to reduce the broadcast overheadby compressing headers of IP packets. In MPEG-2 TS overhead reduction,link layer protocol provides sync byte removal, null packet deletionand/or common header removal (compression). First, sync byte removalprovides an overhead reduction of one byte per TS packet, secondly anull packet deletion mechanism removes the 188 byte null TS packets in amanner that they can be re-inserted at the receiver and finally a commonheader removal mechanism.

For signaling transmission, in the link layer protocol, a particularformat for the signaling packet may be provided for link layersignaling, which will be described below.

In the illustrated link layer protocol architecture according to anembodiment of the present invention, link layer protocol takes as inputnetwork layer packets such as IPv4, MPEG-2 TS and so on as inputpackets. Future extension indicates other packet types and protocolwhich is also possible to be input in link layer. Link layer protocolalso specifies the format and signaling for any link layer signaling,including information about mapping to specific channel to the physicallayer. Figure also shows how ALP incorporates mechanisms to improve theefficiency of transmission, via various header compression and deletionalgorithms. In addition, the link layer protocol may basicallyencapsulate input packets.

FIG. 9 illustrates a structure of a base header of a link layer packetaccording to an embodiment of the present invention. Hereinafter, thestructure of the header will be described.

A link layer packet can include a header followed by the data payload.The header of a link layer packet can include a base header, and mayinclude an additional header depending on the control fields of the baseheader. The presence of an optional header is indicated from flag fieldsof the additional header. According to a given embodiment, a fieldindicating the presence of an additional header and an optional headermay be positioned in the base header.

Hereinafter, the structure of the base header will be described. Thebase header for link layer packet encapsulation has a hierarchicalstructure. The base header can be two bytes in length and is the minimumlength of the link layer packet header.

The illustrated base header according to the present embodiment mayinclude a Packet_Type field, a PC field and/or a length field. Accordingto a given embodiment, the base header may further include an HM fieldor an S/C field.

Packet_Type field can be a 3-bit field that indicates the originalprotocol or packet type of the input data before encapsulation into alink layer packet. An IPv4 packet, a compressed IP packet, a link layersignaling packet, and other types of packets may have the base headerstructure and may be encapsulated. However, according to a givenembodiment, the MPEG-2 TS packet may have a different particularstructure, and may be encapsulated. When the value of Packet_Type is“000”, “001” “100” or “111”, that is the original data type of an ALPpacket is one of an IPv4 packet, a compressed IP packet, link layersignaling or extension packet. When the MPEG-2 TS packet isencapsulated, the value of Packet_Type can be “010”. Other values of thePacket_Type field may be reserved for future use.

Payload_Configuration (PC) field can be a 1-bit field that indicates theconfiguration of the payload. A value of 0 can indicate that the linklayer packet carries a single, whole input packet and the followingfield is the Header_Mode field. A value of 1 can indicate that the linklayer packet carries more than one input packet (concatenation) or apart of a large input packet (segmentation) and the following field isthe Segmentation_Concatenation field.

Header_Mode (HM) field can be a 1-bit field, when set to 0, that canindicate there is no additional header, and that the length of thepayload of the link layer packet is less than 2048 bytes. This value maybe varied depending on embodiments. A value of 1 can indicate that anadditional header for single packet defined below is present followingthe Length field. In this case, the length of the payload is larger than2047 bytes and/or optional features can be used (sub streamidentification, header extension, etc.). This value may be varieddepending on embodiments. This field can be present only whenPayload_Configuration field of the link layer packet has a value of 0.

Segmentation_Concatenation (S/C) field can be a 1-bit field, when set to0, that can indicate that the payload carries a segment of an inputpacket and an additional header for segmentation defined below ispresent following the Length field. A value of 1 can indicate that thepayload carries more than one complete input packet and an additionalheader for concatenation defined below is present following the Lengthfield. This field can be present only when the value ofPayload_Configuration field of the ALP packet is 1.

Length field can be an 11-bit field that indicates the 11 leastsignificant bits (LSBs) of the length in bytes of payload carried by thelink layer packet. When there is a Length_MSB field in the followingadditional header, the length field is concatenated with the Length_MSBfield, and is the LSB to provide the actual total length of the payload.The number of bits of the length field may be changed to another valuerather than 11 bits.

Following types of packet configuration are thus possible: a singlepacket without any additional header, a single packet with an additionalheader, a segmented packet and a concatenated packet. According to agiven embodiment, more packet configurations may be made through acombination of each additional header, an optional header, an additionalheader for signaling information to be described below, and anadditional header for time extension.

FIG. 10 illustrates a structure of an additional header of a link layerpacket according to an embodiment of the present invention.

Various types of additional headers may be present. Hereinafter, adescription will be given of an additional header for a single packet.

This additional header for single packet can be present when Header_Mode(HM)=“1”. The Header_Mode (HM) can be set to 1 when the length of thepayload of the link layer packet is larger than 2047 bytes or when theoptional fields are used. The additional header for single packet isshown in Figure (tsib10010).

Length_MSB field can be a 5-bit field that can indicate the mostsignificant bits (MSBs) of the total payload length in bytes in thecurrent link layer packet, and is concatenated with the Length fieldcontaining the 11 least significant bits (LSBs) to obtain the totalpayload length. The maximum length of the payload that can be signaledis therefore 65535 bytes. The number of bits of the length field may bechanged to another value rather than 11 bits. In addition, the number ofbits of the Length_MSB field may be changed, and thus a maximumexpressible payload length may be changed. According to a givenembodiment, each length field may indicate a length of a whole linklayer packet rather than a payload.

SIF (Sub stream Identifier Flag) field can be a 1-bit field that canindicate whether the sub stream ID (SID) is present after the HEF fieldor not. When there is no SID in this link layer packet, SIF field can beset to 0. When there is a SID after HEF field in the link layer packet,SIF can be set to 1. The detail of SID is described below.

HEF (Header Extension Flag) field can be a 1-bit field that canindicate, when set to 1 additional header is present for futureextension. A value of 0 can indicate that this extension header is notpresent.

Hereinafter, a description will be given of an additional header whensegmentation is used.

This additional header (tsib10020) can be present whenSegmentation_Concatenation (S/C)=“0”. Segment_Sequence_Number can be a5-bit unsigned integer that can indicate the order of the correspondingsegment carried by the link layer packet. For the link layer packetwhich carries the first segment of an input packet, the value of thisfield can be set to 0x0. This field can be incremented by one with eachadditional segment belonging to the segmented input packet.

Last_Segment_Indicator (LSI) can be a 1-bit field that can indicate,when set to 1, that the segment in this payload is the last one of inputpacket. A value of 0, can indicate that it is not last segment.

SIF (Sub stream Identifier Flag) can be a 1-bit field that can indicatewhether the SID is present after the HEF field or not. When there is noSID in the link layer packet, SIF field can be set to 0. When there is aSID after the HEF field in the link layer packet, SIF can be set to 1.

HEF (Header Extension Flag) can be a This 1-bit field that can indicate,when set to 1, that the optional header extension is present after theadditional header for future extensions of the link layer header. Avalue of 0 can indicate that optional header extension is not present.

According to a given embodiment, a packet ID field may be additionallyprovided to indicate that each segment is generated from the same inputpacket. This field may be unnecessary and thus be omitted when segmentsare transmitted in order.

Hereinafter, a description will be given of an additional header whenconcatenation is used.

This additional header (tsib10030) can be present whenSegmentation_Concatenation (S/C)=“1”.

Length_MSB can be a 4-bit field that can indicate MSB bits of thepayload length in bytes in this link layer packet. The maximum length ofthe payload is 32767 bytes for concatenation. As described in theforegoing, a specific numeric value may be changed.

Count can be a field that can indicate the number of the packetsincluded in the link layer packet. The number of the packets included inthe link layer packet, 2 can be set to this field. So, its maximum valueof concatenated packets in a link layer packet is 9. A scheme in whichthe count field indicates the number may be varied depending onembodiments. That is, the numbers from 1 to 8 may be indicated.

HEF (Header Extension Flag) can be a 1-bit field that can indicate, whenset to 1 the optional header extension is present after the additionalheader for future extensions of the link layer header. A value of 0, canindicate extension header is not present.

Component_Length can be a 12-bit length field that can indicate thelength in byte of each packet. Component_Length fields are included inthe same order as the packets present in the payload except lastcomponent packet. The number of length field can be indicated by(Count+1). According to a given embodiment, length fields, the number ofwhich is the same as a value of the count field, may be present. When alink layer header consists of an odd number of Component_Length, fourstuffing bits can follow after the last Component_Length field. Thesebits can be set to 0. According to a given embodiment, aComponent_length field indicating a length of a last concatenated inputpacket may not be present. In this case, the length of the lastconcatenated input packet may correspond to a length obtained bysubtracting a sum of values indicated by respective Component_lengthfields from a whole payload length.

Hereinafter, the optional header will be described.

As described in the foregoing, the optional header may be added to arear of the additional header. The optional header field can contain SIDand/or header extension. The SID is used to filter out specific packetstream in the link layer level. One example of SID is the role ofservice identifier in a link layer stream carrying multiple services.The mapping information between a service and the SID valuecorresponding to the service can be provided in the SLT, if applicable.The header extension contains extended field for future use. Receiverscan ignore any header extensions which they do not understand.

SID (Sub stream Identifier) can be an 8-bit field that can indicate thesub stream identifier for the link layer packet. If there is optionalheader extension, SID present between additional header and optionalheader extension.

Header_Extension ( ) can include the fields defined below.

Extension Type can be an 8-bit field that can indicate the type of theHeader_Extension ( ).

Extension_Length can be an 8-bit field that can indicate the length ofthe Header Extension ( ) in bytes counting from the next byte to thelast byte of the Header_Extension ( ).

Extension_Byte can be a byte representing the value of theHeader_Extension ( ).

FIG. 11 illustrates a structure of an additional header of a link layerpacket according to another embodiment of the present invention.

Hereinafter, a description will be given of an additional header forsignaling information.

How link layer signaling is incorporated into link layer packets are asfollows. Signaling packets are identified by when the Packet_Type fieldof the base header is equal to 100.

Figure (tsib11010) shows the structure of the link layer packetscontaining additional header for signaling information. In addition tothe link layer header, the link layer packet can consist of twoadditional parts, additional header for signaling information and theactual signaling data itself. The total length of the link layersignaling packet is shown in the link layer packet header.

The additional header for signaling information can include followingfields. According to a given embodiment, some fields may be omitted.

Signaling_Type can be an 8-bit field that can indicate the type ofsignaling.

Signaling_Type_Extension can be a 16-bit filed that can indicate theattribute of the signaling. Detail of this field can be defined insignaling specification.

Signaling_Version can be an 8-bit field that can indicate the version ofsignaling.

Signaling_Format can be a 2-bit field that can indicate the data formatof the signaling data. Here, a signaling format may refer to a dataformat such as a binary format, an XML format, etc.

Signaling_Encoding can be a 2-bit field that can specify theencoding/compression format. This field may indicate whether compressionis not performed and which type of compression is performed.

Hereinafter, a description will be given of an additional header forpacket type extension.

In order to provide a mechanism to allow an almost unlimited number ofadditional protocol and packet types to be carried by link layer in thefuture, the additional header is defined. Packet type extension can beused when Packet_type is 111 in the base header as described above.Figure (tsib11020) shows the structure of the link layer packetscontaining additional header for type extension.

The additional header for type extension can include following fields.According to a given embodiment, some fields may be omitted.

extended_type can be a 16-bit field that can indicate the protocol orpacket type of the input encapsulated in the link layer packet aspayload. This field cannot be used for any protocol or packet typealready defined by Packet_Type field.

FIG. 12 illustrates a header structure of a link layer packet for anMPEG-2 TS packet and an encapsulation process thereof according to anembodiment of the present invention.

Hereinafter, a description will be given of a format of the link layerpacket when the MPEG-2 TS packet is input as an input packet.

In this case, the Packet_Type field of the base header is equal to 010.Multiple TS packets can be encapsulated within each link layer packet.The number of TS packets is signaled via the NUMTS field. In this case,as described in the foregoing, a particular link layer packet headerformat may be used.

Link layer provides overhead reduction mechanisms for MPEG-2 TS toenhance the transmission efficiency. The sync byte (0x47) of each TSpacket can be deleted. The option to delete NULL packets and similar TSheaders is also provided.

In order to avoid unnecessary transmission overhead, TS null packets(PID=0x1FFF) may be removed. Deleted null packets can be recovered inreceiver side using DNP field. The DNP field indicates the count ofdeleted null packets. Null packet deletion mechanism using DNP field isdescribed below.

In order to achieve more transmission efficiency, similar header ofMPEG-2 TS packets can be removed. When two or more successive TS packetshave sequentially increased continuity counter fields and other headerfields are the same, the header is sent once at the first packet and theother headers are deleted. HDM field can indicate whether the headerdeletion is performed or not. Detailed procedure of common TS headerdeletion is described below.

When all three overhead reduction mechanisms are performed, overheadreduction can be performed in sequence of sync removal, null packetdeletion, and common header deletion. According to a given embodiment, aperformance order of respective mechanisms may be changed. In addition,some mechanisms may be omitted according to a given embodiment.

The overall structure of the link layer packet header when using MPEG-2TS packet encapsulation is depicted in Figure (tsib12010).

Hereinafter, a description will be given of each illustrated field.Packet_Type can be a 3-bit field that can indicate the protocol type ofinput packet as describe above. For MPEG-2 TS packet encapsulation, thisfield can always be set to 010.

NUMTS (Number of TS packets) can be a 4-bit field that can indicate thenumber of TS packets in the payload of this link layer packet. A maximumof 16 TS packets can be supported in one link layer packet. The value ofNUMTS=0 can indicate that 16 TS packets are carried by the payload ofthe link layer packet. For all other values of NUMTS, the same number ofTS packets are recognized, e.g. NUMTS=0001 means one TS packet iscarried.

AHF (Additional Header Flag) can be a field that can indicate whetherthe additional header is present of not. A value of 0 indicates thatthere is no additional header. A value of 1 indicates that an additionalheader of length 1-byte is present following the base header. If null TSpackets are deleted or TS header compression is applied this field canbe set to 1. The additional header for TS packet encapsulation consistsof the following two fields and is present only when the value of AHF inthis link layer packet is set to 1.

HDM (Header Deletion Mode) can be a 1-bit field that indicates whetherTS header deletion can be applied to this link layer packet. A value of1 indicates that TS header deletion can be applied. A value of “0”indicates that the TS header deletion method is not applied to this linklayer packet.

DNP (Deleted Null Packets) can be a 7-bit field that indicates thenumber of deleted null TS packets prior to this link layer packet. Amaximum of 128 null TS packets can be deleted. When HDM=0 the value ofDNP=0 can indicate that 128 null packets are deleted. When HDM=1 thevalue of DNP=0 can indicate that no null packets are deleted. For allother values of DNP, the same number of null packets are recognized,e.g. DNP=5 means 5 null packets are deleted.

The number of bits of each field described above may be changed.According to the changed number of bits, a minimum/maximum value of avalue indicated by the field may be changed. These numbers may bechanged by a designer.

Hereinafter, SYNC byte removal will be described.

When encapsulating TS packets into the payload of a link layer packet,the SYNC byte (0x47) from the start of each TS packet can be deleted.Hence the length of the MPEG2-TS packet encapsulated in the payload ofthe link layer packet is always of length 187 bytes (instead of 188bytes originally).

Hereinafter, null packet deletion will be described.

Transport Stream rules require that bit rates at the output of atransmitter's multiplexer and at the input of the receiver'sde-multiplexer are constant in time and the end-to-end delay is alsoconstant. For some Transport Stream input signals, null packets may bepresent in order to accommodate variable bitrate services in a constantbitrate stream. In this case, in order to avoid unnecessary transmissionoverhead, TS null packets (that is TS packets with PID=0x1FFF) may beremoved. The process is carried-out in a way that the removed nullpackets can be re-inserted in the receiver in the exact place where theywere originally, thus guaranteeing constant bitrate and avoiding theneed for PCR time stamp updating.

Before generation of a link layer packet, a counter called DNP (DeletedNull-Packets) can first be reset to zero and then incremented for eachdeleted null packet preceding the first non-null TS packet to beencapsulated into the payload of the current link layer packet. Then agroup of consecutive useful TS packets is encapsulated into the payloadof the current link layer packet and the value of each field in itsheader can be determined. After the generated link layer packet isinjected to the physical layer, the DNP is reset to zero. When DNPreaches its maximum allowed value, if the next packet is also a nullpacket, this null packet is kept as a useful packet and encapsulatedinto the payload of the next link layer packet. Each link layer packetcan contain at least one useful TS packet in its payload.

Hereinafter, TS packet header deletion will be described. TS packetheader deletion may be referred to as TS packet header compression.

When two or more successive TS packets have sequentially increasedcontinuity counter fields and other header fields are the same, theheader is sent once at the first packet and the other headers aredeleted. When the duplicated MPEG-2 TS packets are included in two ormore successive TS packets, header deletion cannot be applied intransmitter side. HDM field can indicate whether the header deletion isperformed or not. When TS header deletion is performed, HDM can be setto 1. In the receiver side, using the first packet header, the deletedpacket headers are recovered, and the continuity counter is restored byincreasing it in order from that of the first header.

An example tsib12020 illustrated in the figure is an example of aprocess in which an input stream of a TS packet is encapsulated into alink layer packet. First, a TS stream including TS packets having SYNCbyte (0x47) may be input. First, sync bytes may be deleted through async byte deletion process. In this example, it is presumed that nullpacket deletion is not performed.

Here, it is presumed that packet headers of eight TS packets have thesame field values except for CC, that is, a continuity counter fieldvalue. In this case, TS packet deletion/compression may be performed.Seven remaining TS packet headers are deleted except for a first TSpacket header corresponding to CC=1. The processed TS packets may beencapsulated into a payload of the link layer packet.

In a completed link layer packet, a Packet_Type field corresponds to acase in which TS packets are input, and thus may have a value of 010. ANUMTS field may indicate the number of encapsulated TS packets. An AHFfield may be set to 1 to indicate the presence of an additional headersince packet header deletion is performed. An HDM field may be set to 1since header deletion is performed. DNP may be set to 0 since nullpacket deletion is not performed.

FIG. 13 illustrates an example of adaptation modes in IP headercompression according to an embodiment of the present invention(transmitting side).

Hereinafter, IP header compression will be described.

In the link layer, IP header compression/decompression scheme can beprovided. IP header compression can include two parts: headercompressor/decompressor and adaptation module. The header compressionscheme can be based on the Robust Header Compression (RoHC). Inaddition, for broadcasting usage, adaptation function is added.

In the transmitter side, ROHC compressor reduces the size of header foreach packet. Then, adaptation module extracts context information andbuilds signaling information from each packet stream. In the receiverside, adaptation module parses the signaling information associated withthe received packet stream and attaches context information to thereceived packet stream. ROHC decompressor reconstructs the original IPpacket by recovering the packet header.

The header compression scheme can be based on the RoHC as describedabove. In particular, in the present system, an RoHC framework canoperate in a unidirctional mode (U mode) of the RoHC. In addition, inthe present system, it is possible to use an RoHC UDP header compressionprofile which is identified by a profile identifier of 0x0002.

Hereinafter, adaptation will be described.

In case of transmission through the unidirectional link, if a receiverhas no information of context, decompressor cannot recover the receivedpacket header until receiving full context. This may cause channelchange delay and turn on delay. For this reason, context information andconfiguration parameters between compressor and decompressor can bealways sent with packet flow.

The Adaptation function provides out-of-band transmission of theconfiguration parameters and context information. Out-of-bandtransmission can be done through the link layer signaling. Therefore,the adaptation function is used to reduce the channel change delay anddecompression error due to loss of context information.

Hereinafter, extraction of context information will be described.

Context information may be extracted using various schemes according toadaptation mode. In the present invention, three examples will bedescribed below. The scope of the present invention is not restricted tothe examples of the adaptation mode to be described below. Here, theadaptation mode may be referred to as a context extraction mode.

Adaptation Mode 1 (not illustrated) may be a mode in which no additionaloperation is applied to a basic RoHC packet stream. In other words, theadaptation module may operate as a buffer in this mode. Therefore, inthis mode, context information may not be included in link layersignaling.

In Adaptation Mode 2 (tsib13010), the adaptation module can detect theIR packet from ROHC packet flow and extract the context information(static chain). After extracting the context information, each IR packetcan be converted to an IR-DYN packet. The converted IR-DYN packet can beincluded and transmitted inside the ROHC packet flow in the same orderas IR packet, replacing the original packet.

In Adaptation Mode 3 (tsib13020), the adaptation module can detect theIR and IR-DYN packet from ROHC packet flow and extract the contextinformation. The static chain and dynamic chain can be extracted from IRpacket and dynamic chain can be extracted from IR-DYN packet. Afterextracting the context information, each IR and IR-DYN packet can beconverted to a compressed packet. The compressed packet format can bethe same with the next packet of IR or IR-DYN packet. The convertedcompressed packet can be included and transmitted inside the ROHC packetflow in the same order as IR or IR-DYN packet, replacing the originalpacket.

Signaling (context) information can be encapsulated based ontransmission structure. For example, context information can beencapsulated to the link layer signaling. In this case, the packet typevalue can be set to “100”.

In the above-described Adaptation Modes 2 and 3, a link layer packet forcontext information may have a packet type field value of 100. Inaddition, a link layer packet for compressed IP packets may have apacket type field value of 001. The values indicate that each of thesignaling information and the compressed IP packets are included in thelink layer packet as described above.

Hereinafter, a description will be given of a method of transmitting theextracted context information.

The extracted context information can be transmitted separately fromROHC packet flow, with signaling data through specific physical datapath. The transmission of context depends on the configuration of thephysical layer path. The context information can be sent with other linklayer signaling through the signaling data pipe.

In other words, the link layer packet having the context information maybe transmitted through a signaling PLP together with link layer packetshaving other link layer signaling information (Packet_Type=100).Compressed IP packets from which context information is extracted may betransmitted through a general PLP (Packet_Type=001). Here, depending onembodiments, the signaling PLP may refer to an L1 signaling path. Inaddition, depending on embodiments, the signaling PLP may not beseparated from the general PLP, and may refer to a particular andgeneral PLP through which the signaling information is transmitted.

At a receiving side, prior to reception of a packet stream, a receivermay need to acquire signaling information. When receiver decodes initialPLP to acquire the signaling information, the context signaling can bealso received. After the signaling acquisition is done, the PLP toreceive packet stream can be selected. In other words, the receiver mayacquire the signaling information including the context information byselecting the initial PLP. Here, the initial PLP may be theabove-described signaling PLP. Thereafter, the receiver may select a PLPfor acquiring a packet stream. In this way, the context information maybe acquired prior to reception of the packet stream.

After the PLP for acquiring the packet stream is selected, theadaptation module can detect IR-DYN packet form received packet flow.Then, the adaptation module parses the static chain from the contextinformation in the signaling data. This is similar to receiving the IRpacket. For the same context identifier, IR-DYN packet can be recoveredto IR packet. Recovered ROHC packet flow can be sent to ROHCdecompressor. Thereafter, decompression may be started.

FIG. 14 illustrates a link mapping table (LMT) and an RoHC-U descriptiontable according to an embodiment of the present invention.

Hereinafter, link layer signaling will be described.

Generally, link layer signaling is operates under IP level. At thereceiver side, link layer signaling can be obtained earlier than IPlevel signaling such as Service List Table (SLT) and Service LayerSignaling (SLS). Therefore, link layer signaling can be obtained beforesession establishment.

For link layer signaling, there can be two kinds of signaling accordinginput path: internal link layer signaling and external link layersignaling. The internal link layer signaling is generated in link layerat transmitter side. And the link layer takes the signaling fromexternal module or protocol. This kind of signaling information isconsidered as external link layer signaling. If some signaling need tobe obtained prior to IP level signaling, external signaling istransmitted in format of link layer packet.

The link layer signaling can be encapsulated into link layer packet asdescribed above. The link layer packets can carry any format of linklayer signaling, including binary and XML. The same signalinginformation may not be transmitted in different formats for the linklayer signaling.

Internal link layer signaling may include signaling information for linkmapping. The Link Mapping Table (LMT) provides a list of upper layersessions carried in a PLP. The LMT also provides addition informationfor processing the link layer packets carrying the upper layer sessionsin the link layer.

An example of the LMT (tsib14010) according to the present invention isillustrated.

signaling_type can be an 8-bit unsigned integer field that indicates thetype of signaling carried by this table. The value of signaling_typefield for Link Mapping Table (LMT) can be set to 0x01.

PLP_ID can be an 8-bit field that indicates the PLP corresponding tothis table.

num_session can be an 8-bit unsigned integer field that provides thenumber of upper layer sessions carried in the PLP identified by theabove PLP_ID field. When the value of signaling_type field is 0x01, thisfield can indicate the number of UDP/IP sessions in the PLP.

src_IP_add can be a 32-bit unsigned integer field that contains thesource IP address of an upper layer session carried in the PLPidentified by the PLP_ID field.

dst_IP_add can be a 32-bit unsigned integer field that contains thedestination IP address of an upper layer session carried in the PLPidentified by the PLP_ID field.

src_UDP_port can be a 16-bit unsigned integer field that represents thesource UDP port number of an upper layer session carried in the PLPidentified by the PLP_ID field.

dst_UDP_port can be a 16-bit unsigned integer field that represents thedestination UDP port number of an upper layer session carried in the PLPidentified by the PLP_ID field.

SID_flag can be a 1-bit Boolean field that indicates whether the linklayer packet carrying the upper layer session identified by above 4fields, Src_IP_add, Dst_IP_add, Src_UDP_Port and Dst_UDP_Port, has anSID field in its optional header. When the value of this field is set to0, the link layer packet carrying the upper layer session may not havean SID field in its optional header. When the value of this field is setto 1, the link layer packet carrying the upper layer session can have anSID field in its optional header and the value the SID field can be sameas the following SID field in this table.

compressed_flag can be a 1-bit Boolean field that indicates whether theheader compression is applied the link layer packets carrying the upperlayer session identified by above 4 fields, Src_IP_add, Dst_IP_add,Src_UDP_Port and Dst_UDP_Port. When the value of this field is set to 0,the link layer packet carrying the upper layer session may have a valueof 0x00 of Packet_Type field in its base header. When the value of thisfield is set to 1, the link layer packet carrying the upper layersession may have a value of 0x01 of Packet_Type field in its base headerand the Context_ID field can be present.

SID can be an 8-bit unsigned integer field that indicates sub streamidentifier for the link layer packets carrying the upper layer sessionidentified by above 4 fields, Src_IP_add, Dst_IP_add, Src_UDP_Port andDst_UDP_Port. This field can be present when the value of SID_flag isequal to 1.

context_id can be an 8-bit field that provides a reference for thecontext id (CID) provided in the ROHC-U description table. This fieldcan be present when the value of compressed_flag is equal to 1.

An example of the RoHC-U description table (tsib14020) according to thepresent invention is illustrated. As described in the foregoing, theRoHC-U adaptation module may generate information related to headercompression.

signaling_type can be an 8-bit field that indicates the type ofsignaling carried by this table. The value of signaling_type field forROHC-U description table (RDT) can be set to “0x02”.

PLP_ID can be an 8-bit field that indicates the PLP corresponding tothis table.

context_id can be an 8-bit field that indicates the context id (CID) ofthe compressed IP stream. In this system, 8-bit CID can be used forlarge CID.

context_profile can be an 8-bit field that indicates the range ofprotocols used to compress the stream. This field can be omitted.

adaptation_mode can be a 2-bit field that indicates the mode ofadaptation module in this PLP. Adaptation modes have been describedabove.

context_config can be a 2-bit field that indicates the combination ofthe context information. If there is no context information in thistable, this field may be set to “0x0”. If the static_chain( ) ordynamic_chain( ) byte is included in this table, this field may be setto “0x01” or “0x02” respectively. If both of the static_chain( ) anddynamic_chain( ) byte are included in this table, this field may be setto “0x03”.

context_length can be an 8-bit field that indicates the length of thestatic chain byte sequence. This field can be omitted.

static_chain_byte ( ) can be a field that conveys the static informationused to initialize the ROHC-U decompressor. The size and structure ofthis field depend on the context profile.

dynamic_chain_byte ( ) can be a field that conveys the dynamicinformation used to initialize the ROHC-U decompressor. The size andstructure of this field depend on the context profile.

The static_chain_byte can be defined as sub-header information of IRpacket. The dynamic_chain_byte can be defined as sub-header informationof IR packet and IR-DYN packet.

FIG. 15 illustrates a structure of a link layer on a transmitter sideaccording to an embodiment of the present invention.

The present embodiment presumes that an IP packet is processed. From afunctional point of view, the link layer on the transmitter side maybroadly include a link layer signaling part in which signalinginformation is processed, an overhead reduction part, and/or anencapsulation part. In addition, the link layer on the transmitter sidemay include a scheduler for controlling and scheduling an overalloperation of the link layer and/or input and output parts of the linklayer.

First, signaling information of an upper layer and/or a system parametertsib15010 may be delivered to the link layer. In addition, an IP streamincluding IP packets may be delivered to the link layer from an IP layertsib15110.

As described above, the scheduler tsib15020 may determine and controloperations of several modules included in the link layer. The deliveredsignaling information and/or system parameter tsib15010 may be filtereror used by the scheduler tsib15020. Information, which corresponds to apart of the delivered signaling information and/or system parametertsib15010, necessary for a receiver may be delivered to the link layersignaling part. In addition, information, which corresponds to a part ofthe signaling information, necessary for an operation of the link layermay be delivered to an overhead reduction controller tsib15120 or anencapsulation controller tsib15180.

The link layer signaling part may collect information to be transmittedas a signal in a physical layer, and convert/configure the informationin a form suitable for transmission. The link layer signaling part mayinclude a signaling manager tsib15030, a signaling formatter tsib15040,and/or a buffer for channels tsib15050.

The signaling manager tsib15030 may receive signaling informationdelivered from the scheduler tsib15020 and/or signaling (and/or context)information delivered from the overhead reduction part. The signalingmanager tsib15030 may determine a path for transmission of the signalinginformation for delivered data. The signaling information may bedelivered through the path determined by the signaling managertsib15030. As described in the foregoing, signaling information to betransmitted through a divided channel such as the FIC, the EAS, etc. maybe delivered to the signaling formatter tsib15040, and other signalinginformation may be delivered to an encapsulation buffer tsib15070.

The signaling formatter tsib15040 may format related signalinginformation in a form suitable for each divided channel such thatsignaling information may be transmitted through a separately dividedchannel. As described in the foregoing, the physical layer may includeseparate physically/logically divided channels. The divided channels maybe used to transmit FIC signaling information or EAS-relatedinformation. The FIC or EAS-related information may be sorted by thesignaling manager tsib15030, and input to the signaling formattertsib15040. The signaling formatter tsib15040 may format the informationbased on each separate channel. When the physical layer is designed totransmit particular signaling information through a separately dividedchannel other than the FIC and the EAS, a signaling formatter for theparticular signaling information may be additionally provided. Throughthis scheme, the link layer may be compatible with various physicallayers.

The buffer for channels tsib15050 may deliver the signaling informationreceived from the signaling formatter tsib15040 to separate dedicatedchannels tsib15060. The number and content of the separate channels mayvary depending on embodiments.

As described in the foregoing, the signaling manager tsib15030 maydeliver signaling information, which is not delivered to a particularchannel, to the encapsulation buffer tsib15070. The encapsulation buffertsib15070 may function as a buffer that receives the signalinginformation which is not delivered to the particular channel.

An encapsulation block for signaling information tsib15080 mayencapsulate the signaling information which is not delivered to theparticular channel. A transmission buffer tsib15090 may function as abuffer that delivers the encapsulated signaling information to a DP forsignaling information tsib15100. Here, the DP for signaling informationtsib15100 may refer to the above-described PLS region.

The overhead reduction part may allow efficient transmission by removingoverhead of packets delivered to the link layer. It is possible toconfigure overhead reduction parts corresponding to the number of IPstreams input to the link layer.

An overhead reduction buffer tsib15130 may receive an IP packetdelivered from an upper layer. The received IP packet may be input tothe overhead reduction part through the overhead reduction buffertsib15130.

An overhead reduction controller tsib15120 may determine whether toperform overhead reduction on a packet stream input to the overheadreduction buffer tsib15130. The overhead reduction controller tsib15120may determine whether to perform overhead reduction for each packetstream. When overhead reduction is performed on a packet stream, packetsmay be delivered to a robust header compression (RoHC) compressortsib15140 to perform overhead reduction. When overhead reduction is notperformed on a packet stream, packets may be delivered to theencapsulation part to perform encapsulation without overhead reduction.Whether to perform overhead reduction of packets may be determined basedon the signaling information tsib15010 delivered to the link layer. Thesignaling information may be delivered to the encapsulation controllertsib15180 by the scheduler tsib15020.

The RoHC compressor tsib15140 may perform overhead reduction on a packetstream. The RoHC compressor tsib15140 may perform an operation ofcompressing a header of a packet. Various schemes may be used foroverhead reduction. Overhead reduction may be performed using a schemeproposed by the present invention. The present invention presumes an IPstream, and thus an expression “RoHC compressor” is used. However, thename may be changed depending on embodiments. The operation is notrestricted to compression of the IP stream, and overhead reduction ofall types of packets may be performed by the RoHC compressor tsib15140.

A packet stream configuration block tsib15150 may separate informationto be transmitted to a signaling region and information to betransmitted to a packet stream from IP packets having compressedheaders. The information to be transmitted to the packet stream mayrefer to information to be transmitted to a DP region. The informationto be transmitted to the signaling region may be delivered to asignaling and/or context controller tsib15160. The information to betransmitted to the packet stream may be transmitted to the encapsulationpart.

The signaling and/or context controller tsib15160 may collect signalingand/or context information and deliver the signaling and/or contextinformation to the signaling manager in order to transmit the signalingand/or context information to the signaling region.

The encapsulation part may perform an operation of encapsulating packetsin a form suitable for a delivery to the physical layer. It is possibleto configure encapsulation parts corresponding to the number of IPstreams.

An encapsulation buffer tsib15170 may receive a packet stream forencapsulation. Packets subjected to overhead reduction may be receivedwhen overhead reduction is performed, and an input IP packet may bereceived without change when overhead reduction is not performed.

An encapsulation controller tsib15180 may determine whether toencapsulate an input packet stream. When encapsulation is performed, thepacket stream may be delivered to a segmentation/concatenation blocktsib15190. When encapsulation is not performed, the packet stream may bedelivered to a transmission buffer tsib15230. Whether to encapsulatepackets may be determined based on the signaling information tsib15010delivered to the link layer. The signaling information may be deliveredto the encapsulation controller tsib15180 by the scheduler tsib15020.

In the segmentation/concatenation block tsib15190, the above-describedsegmentation or concatenation operation may be performed on packets. Inother words, when an input IP packet is longer than a link layer packetcorresponding to an output of the link layer, one IP packet may besegmented into several segments to configure a plurality of link layerpacket payloads. On the other hand, when an input IP packet is shorterthan a link layer packet corresponding to an output of the link layer,several IP packets may be concatenated to configure one link layerpacket payload.

A packet configuration table tsib15200 may have configurationinformation of a segmented and/or concatenated link layer packet. Atransmitter and a receiver may have the same information in the packetconfiguration table tsib15200. The transmitter and the receiver mayrefer to the information of the packet configuration table tsib15200. Anindex value of the information of the packet configuration tabletsib15200 may be included in a header of the link layer packet.

A link layer header information block tsib15210 may collect headerinformation generated in an encapsulation process. In addition, the linklayer header information block tsib15210 may collect header informationincluded in the packet configuration table tsib15200. The link layerheader information block tsib15210 may configure header informationaccording to a header structure of the link layer packet.

A header attachment block tsib15220 may add a header to a payload of asegmented and/or concatenated link layer packet. The transmission buffertsib15230 may function as a buffer to deliver the link layer packet to aDP tsib15240 of the physical layer.

The respective blocks, modules, or parts may be configured as onemodule/protocol or a plurality of modules/protocols in the link layer.

FIG. 16 illustrates a structure of a link layer on a receiver sideaccording to an embodiment of the present invention.

The present embodiment presumes that an IP packet is processed. From afunctional point of view, the link layer on the receiver side maybroadly include a link layer signaling part in which signalinginformation is processed, an overhead processing part, and/or adecapsulation part. In addition, the link layer on the receiver side mayinclude a scheduler for controlling and scheduling overall operation ofthe link layer and/or input and output parts of the link layer.

First, information received through a physical layer may be delivered tothe link layer. The link layer may process the information, restore anoriginal state before being processed at a transmitter side, and thendeliver the information to an upper layer. In the present embodiment,the upper layer may be an IP layer.

Information, which is separated in the physical layer and deliveredthrough a particular channel tsib16030, may be delivered to a link layersignaling part. The link layer signaling part may determine signalinginformation received from the physical layer, and deliver the determinedsignaling information to each part of the link layer.

A buffer for channels tsib16040 may function as a buffer that receivessignaling information transmitted through particular channels. Asdescribed in the foregoing, when physically/logically divided separatechannels are present in the physical layer, it is possible to receivesignaling information transmitted through the channels. When theinformation received from the separate channels is segmented, thesegmented information may be stored until complete information isconfigured.

A signaling decoder/parser tsib16050 may verify a format of thesignaling information received through the particular channel, andextract information to be used in the link layer. When the signalinginformation received through the particular channel is encoded, decodingmay be performed. In addition, according to a given embodiment, it ispossible to verify integrity, etc. of the signaling information.

A signaling manager tsib16060 may integrate signaling informationreceived through several paths. Signaling information received through aDP for signaling tsib16070 to be described below may be integrated inthe signaling manager tsib16060. The signaling manager tsib16060 maydeliver signaling information necessary for each part in the link layer.For example, the signaling manager tsib16060 may deliver contextinformation, etc. for recovery of a packet to the overhead processingpart. In addition, the signaling manager tsib16060 may deliver signalinginformation for control to a scheduler tsib16020.

General signaling information, which is not received through a separateparticular channel, may be received through the DP for signalingtsib16070. Here, the DP for signaling may refer to PLS, L1, etc. Here,the DP may be referred to as a PLP. A reception buffer tsib16080 mayfunction as a buffer that receives signaling information delivered fromthe DP for signaling. In a decapsulation block for signaling informationtsib16090, the received signaling information may be decapsulated. Thedecapsulated signaling information may be delivered to the signalingmanager tsib16060 through a decapsulation buffer tsib16100. As describedin the foregoing, the signaling manager tsib16060 may collate signalinginformation, and deliver the collated signaling information to anecessary part in the link layer.

The scheduler tsib16020 may determine and control operations of severalmodules included in the link layer. The scheduler tsib16020 may controleach part of the link layer using receiver information tsib16010 and/orinformation delivered from the signaling manager tsib16060. In addition,the scheduler tsib16020 may determine an operation mode, etc. of eachpart. Here, the receiver information tsib16010 may refer to informationpreviously stored in the receiver. The scheduler tsib16020 may useinformation changed by a user such as channel switching, etc. to performa control operation.

The decapsulation part may filter a packet received from a DP tsib16110of the physical layer, and separate a packet according to a type of thepacket. It is possible to configure decapsulation parts corresponding tothe number of DPs that can be simultaneously decoded in the physicallayer.

The decapsulation buffer tsib16100 may function as a buffer thatreceives a packet stream from the physical layer to performdecapsulation. A decapsulation controller tsib16130 may determinewhether to decapsulate an input packet stream. When decapsulation isperformed, the packet stream may be delivered to a link layer headerparser tsib16140. When decapsulation is not performed, the packet streammay be delivered to an output buffer tsib16220. The signalinginformation received from the scheduler tsib16020 may be used todetermine whether to perform decapsulation.

The link layer header parser tsib16140 may identify a header of thedelivered link layer packet. It is possible to identify a configurationof an IP packet included in a payload of the link layer packet byidentifying the header. For example, the IP packet may be segmented orconcatenated.

A packet configuration table tsib16150 may include payload informationof segmented and/or concatenated link layer packets. The transmitter andthe receiver may have the same information in the packet configurationtable tsib16150. The transmitter and the receiver may refer to theinformation of the packet configuration table tsib16150. It is possibleto find a value necessary for reassembly based on index informationincluded in the link layer packet.

A reassembly block tsib16160 may configure payloads of the segmentedand/or concatenated link layer packets as packets of an original IPstream. Segments may be collected and reconfigured as one IP packet, orconcatenated packets may be separated and reconfigured as a plurality ofIP packet streams. Recombined IP packets may be delivered to theoverhead processing part.

The overhead processing part may perform an operation of restoring apacket subjected to overhead reduction to an original packet as areverse operation of overhead reduction performed in the transmitter.This operation may be referred to as overhead processing. It is possibleto configure overhead processing parts corresponding to the number ofDPs that can be simultaneously decoded in the physical layer.

A packet recovery buffer tsib16170 may function as a buffer thatreceives a decapsulated RoHC packet or IP packet to perform overheadprocessing.

An overhead controller tsib16180 may determine whether to recover and/ordecompress the decapsulated packet. When recovery and/or decompressionare performed, the packet may be delivered to a packet stream recoveryblock tsib16190. When recovery and/or decompression are not performed,the packet may be delivered to the output buffer tsib16220. Whether toperform recovery and/or decompression may be determined based on thesignaling information delivered by the scheduler tsib16020.

The packet stream recovery block tsib16190 may perform an operation ofintegrating a packet stream separated from the transmitter with contextinformation of the packet stream. This operation may be a process ofrestoring a packet stream such that an RoHC decompressor tsib16210 canperform processing. In this process, it is possible to receive signalinginformation and/or context information from a signaling and/or contextcontroller tsib16200. The signaling and/or context controller tsib16200may determine signaling information delivered from the transmitter, anddeliver the signaling information to the packet stream recovery blocktsib16190 such that the signaling information may be mapped to a streamcorresponding to a context ID.

The RoHC decompressor tsib16210 may restore headers of packets of thepacket stream. The packets of the packet stream may be restored to formsof original IP packets through restoration of the headers. In otherwords, the RoHC decompressor tsib16210 may perform overhead processing.

The output buffer tsib16220 may function as a buffer before an outputstream is delivered to an IP layer tsib16230.

The link layers of the transmitter and the receiver proposed in thepresent invention may include the blocks or modules described above. Inthis way, the link layer may independently operate irrespective of anupper layer and a lower layer, overhead reduction may be efficientlyperformed, and a supportable function according to an upper/lower layermay be easily defined/added/deleted.

FIG. 17 illustrates a configuration of signaling transmission through alink layer according to an embodiment of the present invention(transmitting/receiving sides).

In the present invention, a plurality of service providers(broadcasters) may provide services within one frequency band. Inaddition, a service provider may provide a plurality of services, andone service may include one or more components. It can be consideredthat the user receives content using a service as a unit.

The present invention presumes that a transmission protocol based on aplurality of sessions is used to support an IP hybrid broadcast.Signaling information delivered through a signaling path may bedetermined based on a transmission configuration of each protocol.Various names may be applied to respective protocols according to agiven embodiment.

In the illustrated data configuration tsib17010 on the transmittingside, service providers (broadcasters) may provide a plurality ofservices (Service #1, #2, . . . ). In general, a signal for a servicemay be transmitted through a general transmission session (signaling C).However, the signal may be transmitted through a particular session(dedicated session) according to a given embodiment (signaling B).

Service data and service signaling information may be encapsulatedaccording to a transmission protocol. According to a given embodiment,an IP/UDP layer may be used. According to a given embodiment, a signalin the IP/UDP layer (signaling A) may be additionally provided. Thissignaling may be omitted.

Data processed using the IP/UDP may be input to the link layer. Asdescribed in the foregoing, overhead reduction and/or encapsulation maybe performed in the link layer. Here, link layer signaling may beadditionally provided. Link layer signaling may include a systemparameter, etc. Link layer signaling has been described above.

The service data and the signaling information subjected to the aboveprocess may be processed through PLPs in a physical layer. Here, a PLPmay be referred to as a DP. The example illustrated in the figurepresumes a case in which a base DP/PLP is used. However, depending onembodiments, transmission may be performed using only a general DP/PLPwithout the base DP/PLP.

In the example illustrated in the figure, a particular channel(dedicated channel) such as an FIC, an EAC, etc. is used. A signaldelivered through the FIC may be referred to as a fast information table(FIT), and a signal delivered through the EAC may be referred to as anemergency alert table (EAT). The FIT may be identical to theabove-described SLT. The particular channels may not be used dependingon embodiments. When the particular channel (dedicated channel) is notconfigured, the FIT and the EAT may be transmitted using a general linklayer signaling transmission scheme, or transmitted using a PLP via theIP/UDP as other service data.

According to a given embodiment, system parameters may include atransmitter-related parameter, a service provider-related parameter,etc. Link layer signaling may include IP header compression-relatedcontext information and/or identification information of data to whichthe context is applied. Signaling of an upper layer may include an IPaddress, a UDP number, service/component information, emergencyalert-related information, an IP/UDP address for service signaling, asession ID, etc. Detailed examples thereof have been described above.

In the illustrated data configuration tsib17020 on the receiving side,the receiver may decode only a PLP for a corresponding service usingsignaling information without having to decode all PLPs.

First, when the user selects or changes a service desired to bereceived, the receiver may be tuned to a corresponding frequency and mayread receiver information related to a corresponding channel stored in aDB, etc. The information stored in the DB, etc. of the receiver may beconfigured by reading an SLT at the time of initial channel scan.

After receiving the SLT and the information about the correspondingchannel, information previously stored in the DB is updated, andinformation about a transmission path of the service selected by theuser and information about a path, through which component informationis acquired or a signal necessary to acquire the information istransmitted, are acquired. When the information is not determined to bechanged using version information of the SLT, decoding or parsing may beomitted.

The receiver may verify whether SLT information is included in a PLP byparsing physical signaling of the PLP in a corresponding broadcaststream (not illustrated), which may be indicated through a particularfield of physical signaling. It is possible to access a position atwhich a service layer signal of a particular service is transmitted byaccessing the SLT information. The service layer signal may beencapsulated into the IP/UDP and delivered through a transmissionsession. It is possible to acquire information about a componentincluded in the service using this service layer signaling. A specificSLT-SLS configuration is as described above.

In other words, it is possible to acquire transmission path information,for receiving upper layer signaling information (service signalinginformation) necessary to receive the service, corresponding to one ofseveral packet streams and PLPs currently transmitted on a channel usingthe SLT. The transmission path information may include an IP address, aUDP port number, a session ID, a PLP ID, etc. Here, depending onembodiments, a value previously designated by the IANA or a system maybe used as an IP/UDP address. The information may be acquired using ascheme of accessing a DB or a shared memory, etc.

When the link layer signal and service data are transmitted through thesame PLP, or only one PLP is operated, service data delivered throughthe PLP may be temporarily stored in a device such as a buffer, etc.while the link layer signal is decoded.

It is possible to acquire information about a path through which theservice is actually transmitted using service signaling information of aservice to be received. In addition, a received packet stream may besubjected to decapsulation and header recovery using information such asoverhead reduction for a PLP to be received, etc.

In the illustrated example (tsib17020), the FIC and the EAC are used,and a concept of the base DP/PLP is presumed. As described in theforegoing, concepts of the FIC, the EAC, and the base DP/PLP may not beused.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas. The present invention proposes a physical profile (orsystem) optimized to minimize receiver complexity while attaining theperformance required for a particular use case. Physical (PHY) profiles(base, handheld and advanced profiles) according to an embodiment of thepresent invention are subsets of all configurations that a correspondingreceiver should implement. The PHY profiles share most of the functionalblocks but differ slightly in specific blocks and/or parameters. For thesystem evolution, future profiles may also be multiplexed with existingprofiles in a single radio frequency (RF) channel through a futureextension frame (FEF). The base profile and the handheld profileaccording to the embodiment of the present invention refer to profilesto which MIMO is not applied, and the advanced profile refers to aprofile to which MIMO is applied. The base profile may be used as aprofile for both the terrestrial broadcast service and the mobilebroadcast service. That is, the base profile may be used to define aconcept of a profile which includes the mobile profile. In addition, theadvanced profile may be divided into an advanced profile for a baseprofile with MIMO and an advanced profile for a handheld profile withMIMO. Moreover, the profiles may be changed according to intention ofthe designer.

The following terms and definitions may be applied to the presentinvention. The following terms and definitions may be changed accordingto design.

Auxiliary stream: sequence of cells carrying data of as yet undefinedmodulation and coding, which may be used for future extensions or asrequired by broadcasters or network operators

Base data pipe: data pipe that carries service signaling data

Baseband frame (or BBFRAME): set of Kbch bits which form the input toone FEC encoding process (BCH and LDPC encoding)

Cell: modulation value that is carried by one carrier of orthogonalfrequency division multiplexing (OFDM) transmission

Coded block: LDPC-encoded block of PLS1 data or one of the LDPC-encodedblocks of PLS2 data

Data pipe: logical channel in the physical layer that carries servicedata or related metadata, which may carry one or a plurality ofservice(s) or service component(s).

Data pipe unit (DPU): a basic unit for allocating data cells to a DP ina frame.

Data symbol: OFDM symbol in a frame which is not a preamble symbol (thedata symbol encompasses the frame signaling symbol and frame edgesymbol)

DP_ID: this 8-bit field identifies uniquely a DP within the systemidentified by the SYSTEM_ID

Dummy cell: cell carrying a pseudo-random value used to fill theremaining capacity not used for PLS signaling, DPs or auxiliary streams

Emergency alert channel (EAC): part of a frame that carries EASinformation data

Frame: physical layer time slot that starts with a preamble and endswith a frame edge symbol

Frame repetition unit: a set of frames belonging to the same ordifferent physical layer profiles including an FEF, which is repeatedeight times in a superframe

Fast information channel (FIC): a logical channel in a frame thatcarries mapping information between a service and the corresponding baseDP

FECBLOCK: set of LDPC-encoded bits of DP data

FFT size: nominal FFT size used for a particular mode, equal to theactive symbol period Ts expressed in cycles of an elementary period T

Frame signaling symbol: OFDM symbol with higher pilot density used atthe start of a frame in certain combinations of FFT size, guard intervaland scattered pilot pattern, which carries a part of the PLS data

Frame edge symbol: OFDM symbol with higher pilot density used at the endof a frame in certain combinations of FFT size, guard interval andscattered pilot pattern

Frame group: the set of all frames having the same PHY profile type in asuperframe

Future extension frame: physical layer time slot within the superframethat may be used for future extension, which starts with a preamble

Futurecast UTB system: proposed physical layer broadcast system, theinput of which is one or more MPEG2-TS, IP or general stream(s) and theoutput of which is an RF signal

Input stream: a stream of data for an ensemble of services delivered tothe end users by the system

Normal data symbol: data symbol excluding the frame signaling symbol andthe frame edge symbol

PHY profile: subset of all configurations that a corresponding receivershould implement

PLS: physical layer signaling data including PLS1 and PLS2

PLS1: a first set of PLS data carried in a frame signaling symbol (FSS)having a fixed size, coding and modulation, which carries basicinformation about a system as well as parameters needed to decode PLS2

NOTE: PLS1 data remains constant for the duration of a frame group

PLS2: a second set of PLS data transmitted in the FSS, which carriesmore detailed PLS data about the system and the DPs

PLS2 dynamic data: PLS2 data that dynamically changes frame-by-frame

PLS2 static data: PLS2 data that remains static for the duration of aframe group

Preamble signaling data: signaling data carried by the preamble symboland used to identify the basic mode of the system

Preamble symbol: fixed-length pilot symbol that carries basic PLS dataand is located at the beginning of a frame

The preamble symbol is mainly used for fast initial band scan to detectthe system signal, timing thereof, frequency offset, and FFT size.

Reserved for future use: not defined by the present document but may bedefined in future

Superframe: set of eight frame repetition units

Time interleaving block (TI block): set of cells within which timeinterleaving is carried out, corresponding to one use of a timeinterleaver memory

TI group: unit over which dynamic capacity allocation for a particularDP is carried out, made up of an integer, dynamically varying number ofXFECBLOCKs

NOTE: The TI group may be mapped directly to one frame or may be mappedto a plurality of frames. The TI group may contain one or more TIblocks.

Type 1 DP: DP of a frame where all DPs are mapped to the frame in timedivision multiplexing (TDM) scheme

Type 2 DP: DP of a frame where all DPs are mapped to the frame infrequency division multiplexing (FDM) scheme

XFECBLOCK: set of Ncells cells carrying all the bits of one LDPCFECBLOCK

FIG. 18 illustrates a configuration of a broadcast signal transmissionapparatus for future broadcast services according to an embodiment ofthe present invention.

The broadcast signal transmission apparatus for future broadcastservices according to the present embodiment may include an inputformatting block 1000, a bit interleaved coding & modulation (BICM)block 1010, a frame building block 1020, an OFDM generation block 1030and a signaling generation block 1040. Description will be given of anoperation of each block of the broadcast signal transmission apparatus.

In input data according to an embodiment of the present invention, IPstream/packets and MPEG2-TS may be main input formats, and other streamtypes are handled as general streams. In addition to these data inputs,management information is input to control scheduling and allocation ofthe corresponding bandwidth for each input stream. In addition, thepresent invention allows simultaneous input of one or a plurality of TSstreams, IP stream(s) and/or a general stream(s).

The input formatting block 1000 may demultiplex each input stream intoone or a plurality of data pipes, to each of which independent codingand modulation are applied. A DP is the basic unit for robustnesscontrol, which affects QoS. One or a plurality of services or servicecomponents may be carried by one DP. The DP is a logical channel in aphysical layer for delivering service data or related metadata capableof carrying one or a plurality of services or service components.

In addition, a DPU is a basic unit for allocating data cells to a DP inone frame.

An input to the physical layer may include one or a plurality of datastreams. Each of the data streams is delivered by one DP. The inputformatting block 1000 may covert a data stream input through one or morephysical paths (or DPs) into a baseband frame (BBF). In this case, theinput formatting block 1000 may perform null packet deletion or headercompression on input data (a TS or IP input stream) in order to enhancetransmission efficiency. A receiver may have a priori information for aparticular part of a header, and thus this known information may bedeleted from a transmitter. A null packet deletion block 3030 may beused only for a TS input stream.

In the BICM block 1010, parity data is added for error correction andencoded bit streams are mapped to complex-value constellation symbols.The symbols are interleaved across a specific interleaving depth that isused for the corresponding DP. For the advanced profile, MIMO encodingis performed in the BICM block 1010 and an additional data path is addedat the output for MIMO transmission.

The frame building block 1020 may map the data cells of the input DPsinto the OFDM symbols within a frame, and perform frequency interleavingfor frequency-domain diversity, especially to combat frequency-selectivefading channels. The frame building block 1020 may include a delaycompensation block, a cell mapper and a frequency interleaver.

The delay compensation block may adjust timing between DPs andcorresponding PLS data to ensure that the DPs and the corresponding PLSdata are co-timed at a transmitter side. The PLS data is delayed by thesame amount as the data pipes by addressing the delays of data pipescaused by the input formatting block and BICM block. The delay of theBICM block is mainly due to the time interleaver. In-band signaling datacarries information of the next TI group so that the information iscarried one frame ahead of the DPs to be signaled. The delaycompensation block delays in-band signaling data accordingly.

The cell mapper may map PLS, DPs, auxiliary streams, dummy cells, etc.to active carriers of the OFDM symbols in the frame. The basic functionof the cell mapper 7010 is to map data cells produced by the TIs foreach of the DPs, PLS cells, and EAC/FIC cells, if any, into arrays ofactive OFDM cells corresponding to each of the OFDM symbols within aframe. A basic function of the cell mapper is to map a data cellgenerated by time interleaving for each DP and PLS cell to an array ofactive OFDM cells (if present) corresponding to respective OFDM symbolsin one frame. Service signaling data (such as program specificinformation (PSI)/SI) may be separately gathered and sent by a DP. Thecell mapper operates according to dynamic information produced by ascheduler and the configuration of a frame structure. The frequencyinterleaver may randomly interleave data cells received from the cellmapper to provide frequency diversity. In addition, the frequencyinterleaver may operate on an OFDM symbol pair including two sequentialOFDM symbols using a different interleaving-seed order to obtain maximuminterleaving gain in a single frame.

The OFDM generation block 1030 modulates OFDM carriers by cells producedby the frame building block, inserts pilots, and produces a time domainsignal for transmission. In addition, this block subsequently insertsguard intervals, and applies peak-to-average power ratio (PAPR)reduction processing to produce a final RF signal.

Specifically, after inserting a preamble at the beginning of each frame,the OFDM generation block 1030 may apply conventional OFDM modulationhaving a cyclic prefix as a guard interval. For antenna space diversity,a distributed MISO scheme is applied across transmitters. In addition, aPAPR scheme is performed in the time domain. For flexible networkplanning, the present invention provides a set of various FFT sizes,guard interval lengths and corresponding pilot patterns.

In addition, the present invention may multiplex signals of a pluralityof broadcast transmission/reception systems in the time domain such thatdata of two or more different broadcast transmission/reception systemsproviding broadcast services may be simultaneously transmitted in thesame RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc.

The signaling generation block 1040 may create physical layer signalinginformation used for an operation of each functional block. Thissignaling information is also transmitted so that services of interestare properly recovered at a receiver side. Signaling informationaccording to an embodiment of the present invention may include PLSdata. PLS provides the receiver with a means to access physical layerDPs. The PLS data includes PLS1 data and PLS2 data.

The PLS1 data is a first set of PLS data carried in an FSS symbol in aframe having a fixed size, coding and modulation, which carries basicinformation about the system in addition to the parameters needed todecode the PLS2 data. The PLS1 data provides basic transmissionparameters including parameters required to enable reception anddecoding of the PLS2 data. In addition, the PLS1 data remains constantfor the duration of a frame group.

The PLS2 data is a second set of PLS data transmitted in an FSS symbol,which carries more detailed PLS data about the system and the DPs. ThePLS2 contains parameters that provide sufficient information for thereceiver to decode a desired DP. The PLS2 signaling further includes twotypes of parameters, PLS2 static data (PLS2-STAT data) and PLS2 dynamicdata (PLS2-DYN data). The PLS2 static data is PLS2 data that remainsstatic for the duration of a frame group and the PLS2 dynamic data isPLS2 data that dynamically changes frame by frame. Details of the PLSdata will be described later.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 19 illustrates a BICM block according to an embodiment of thepresent invention.

The BICM block illustrated in FIG. 19 corresponds to an embodiment ofthe BICM block 1010 described with reference to FIG. 18.

As described above, the broadcast signal transmission apparatus forfuture broadcast services according to the embodiment of the presentinvention may provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS depends on characteristics of a service provided by thebroadcast signal transmission apparatus for future broadcast servicesaccording to the embodiment of the present invention, data correspondingto respective services needs to be processed using different schemes.Accordingly, the BICM block according to the embodiment of the presentinvention may independently process respective DPs by independentlyapplying SISO, MISO and MIMO schemes to data pipes respectivelycorresponding to data paths. Consequently, the broadcast signaltransmission apparatus for future broadcast services according to theembodiment of the present invention may control QoS for each service orservice component transmitted through each DP.

(a) shows a BICM block applied to a profile (or system) to which MIMO isnot applied, and (b) shows a BICM block of a profile (or system) towhich MIMO is applied.

The BICM block to which MIMO is not applied and the BICM block to whichMIMO is applied may include a plurality of processing blocks forprocessing each DP.

Description will be given of each processing block of the BICM block towhich MIMO is not applied and the BICM block to which MIMO is applied.

A processing block 5000 of the BICM block to which MIMO is not appliedmay include a data FEC encoder 5010, a bit interleaver 5020, aconstellation mapper 5030, a signal space diversity (SSD) encoding block5040 and a time interleaver 5050.

The data FEC encoder 5010 performs FEC encoding on an input BBF togenerate FECBLOCK procedure using outer coding (BCH) and inner coding(LDPC). The outer coding (BCH) is optional coding method. A detailedoperation of the data FEC encoder 5010 will be described later.

The bit interleaver 5020 may interleave outputs of the data FEC encoder5010 to achieve optimized performance with a combination of LDPC codesand a modulation scheme while providing an efficiently implementablestructure. A detailed operation of the bit interleaver 5020 will bedescribed later.

The constellation mapper 5030 may modulate each cell word from the bitinterleaver 5020 in the base and the handheld profiles, or each cellword from the cell-word demultiplexer 5010-1 in the advanced profileusing either QPSK, QAM-16, non-uniform QAM (NUQ-64, NUQ-256, orNUQ-1024) or non-uniform constellation (NUC-16, NUC-64, NUC-256, orNUC-1024) mapping to give a power-normalized constellation point, el.This constellation mapping is applied only for DPs. It is observed thatQAM-16 and NUQs are square shaped, while NUCs have arbitrary shapes.When each constellation is rotated by any multiple of 90 degrees, therotated constellation exactly overlaps with its original one. This“rotation-sense” symmetric property makes the capacities and the averagepowers of the real and imaginary components equal to each other. BothNUQs and NUCs are defined specifically for each code rate and theparticular one used is signaled by the parameter DP_MOD filed in thePLS2 data.

The time interleaver 5050 may operates at a DP level. Parameters of timeinterleaving (TI) may be set differently for each DP. A detailedoperation of the time interleaver 5050 will be described later.

A processing block 5000-1 of the BICM block to which MIMO is applied mayinclude the data FEC encoder, the bit interleaver, the constellationmapper, and the time interleaver.

However, the processing block 5000-1 is distinguished from theprocessing block 5000 of the BICM block to which MIMO is not applied inthat the processing block 5000-1 further includes a cell-worddemultiplexer 5010-1 and a MIMO encoding block 5020-1.

In addition, operations of the data FEC encoder, the bit interleaver,the constellation mapper, and the time interleaver in the processingblock 5000-1 correspond to those of the data FEC encoder 5010, the bitinterleaver 5020, the constellation mapper 5030, and the timeinterleaver 5050 described above, and thus description thereof isomitted.

The cell-word demultiplexer 5010-1 is used for a DP of the advancedprofile to divide a single cell-word stream into dual cell-word streamsfor MIMO processing.

The MIMO encoding block 5020-1 may process an output of the cell-worddemultiplexer 5010-1 using a MIMO encoding scheme. The MIMO encodingscheme is optimized for broadcast signal transmission. MIMO technologyis a promising way to obtain a capacity increase but depends on channelcharacteristics. Especially for broadcasting, a strong LOS component ofa channel or a difference in received signal power between two antennascaused by different signal propagation characteristics makes itdifficult to obtain capacity gain from MIMO. The proposed MIMO encodingscheme overcomes this problem using rotation-based precoding and phaserandomization of one of MIMO output signals.

MIMO encoding is intended for a 2×2 MIMO system requiring at least twoantennas at both the transmitter and the receiver. A MIMO encoding modeof the present invention may be defined as full-rate spatialmultiplexing (FR-SM). FR-SM encoding may provide capacity increase withrelatively small complexity increase at the receiver side. In addition,the MIMO encoding scheme of the present invention has no restriction onan antenna polarity configuration.

MIMO processing is applied at the DP level. NUQ (e1,i and e2,i)corresponding to a pair of constellation mapper outputs is fed to aninput of a MIMO encoder. Paired MIMO encoder output (g1,i and g2,i) istransmitted by the same carrier k and OFDM symbol 1 of respective TXantennas thereof.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 20 illustrates a BICM block according to another embodiment of thepresent invention.

The BICM block illustrated in FIG. 20 corresponds to another embodimentof the BICM block 1010 described with reference to FIG. 18.

FIG. 20 illustrates a BICM block for protection of physical layersignaling (PLS), an emergency alert channel (EAC) and a fast informationchannel (FIC). The EAC is a part of a frame that carries EAS informationdata, and the FIC is a logical channel in a frame that carries mappinginformation between a service and a corresponding base DP. Details ofthe EAC and FIC will be described later.

Referring to FIG. 20, the BICM block for protection of the PLS, the EACand the FIC may include a PLS FEC encoder 6000, a bit interleaver 6010and a constellation mapper 6020.

In addition, the PLS FEC encoder 6000 may include a scrambler, a BCHencoding/zero insertion block, an LDPC encoding block and an LDPC paritypuncturing block. Description will be given of each block of the BICMblock.

The PLS FEC encoder 6000 may encode scrambled PLS 1/2 data. EAC and FICsections.

The scrambler may scramble PLS1 data and PLS2 data before BCH encodingand shortened and punctured LDPC encoding.

The BCH encoding/zero insertion block may perform outer encoding on thescrambled PLS 1/2 data using a shortened BCH code for PLS protection,and insert zero bits after BCH encoding. For PLS1 data only, output bitsof zero insertion may be permutted before LDPC encoding.

The LDPC encoding block may encode an output of the BCH encoding/zeroinsertion block using an LDPC code. To generate a complete coded block,Cldpc and parity bits Pldpc are encoded systematically from eachzero-inserted PLS information block Ildpc and appended thereto.C _(ldpc)=[I _(ldpc) P _(ldpc)]=[i ₀ ,i ₁ , . . . ,i _(K) _(ldpc) ⁻¹ ,p₀ ,p ₁ , . . . ,p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹]  [Equation 1]

The LDPC parity puncturing block may perform puncturing on the PLS1 dataand the PLS2 data.

When shortening is applied to PLS1 data protection, some LDPC paritybits are punctured after LDPC encoding. In addition, for PLS2 dataprotection, LDPC parity bits of PLS2 are punctured after LDPC encoding.These punctured bits are not transmitted.

The bit interleaver 6010 may interleave each of shortened and puncturedPLS1 data and PLS2 data.

The constellation mapper 6020 may map the bit-interleaved PLS1 data andPLS2 data to constellations.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 21 illustrates a bit interleaving process of PLS according to anembodiment of the present invention.

Each shortened and punctured PLS1 and PLS2 coded block is interleavedbit-by-bit as described in FIG. 22. Each block of additional parity bitsis interleaved with the same block interleaving structure butseparately.

In the case of BPSK, there are two branches for bit interleaving toduplicate FEC coded bits in the real and imaginary parts. Each codedblock is written to the upper branch first. The bits are mapped to thelower branch by applying modulo NFEC addition with cyclic shifting valuefloor(NFEC/2), where NFEC is the length of each LDPC coded block aftershortening and puncturing.

In other modulation cases, such as QSPK, QAM-16 and NUQ-64, FEC codedbits are written serially into the interleaver column-wise, where thenumber of columns is the same as the modulation order.

In the read operation, the bits for one constellation symbol are readout sequentially row-wise and fed into the bit demultiplexer block.These operations are continued until the end of the column.

Each bit interleaved group is demultiplexed bit-by-bit in a group beforeconstellation mapping. Depending on modulation order, there are twomapping rules. In the case of BPSK and QPSK, the reliability of bits ina symbol is equal. Therefore, the bit group read out from the bitinterleaving block is mapped to a QAM symbol without any operation.

In the cases of QAM-16 and NUQ-64 mapped to a QAM symbol, the rule ofoperation is described in FIG. 23(a). As shown in FIG. 23(a), i is bitgroup index corresponding to column index in bit interleaving.

FIG. 21 shows the bit demultiplexing rule for QAM-16. This operationcontinues until all bit groups are read from the bit interleaving block.

FIG. 22 illustrates a configuration of a broadcast signal receptionapparatus for future broadcast services according to an embodiment ofthe present invention.

The broadcast signal reception apparatus for future broadcast servicesaccording to the embodiment of the present invention may correspond tothe broadcast signal transmission apparatus for future broadcastservices described with reference to FIG. 18.

The broadcast signal reception apparatus for future broadcast servicesaccording to the embodiment of the present invention may include asynchronization & demodulation module 9000, a frame parsing module 9010,a demapping & decoding module 9020, an output processor 9030 and asignaling decoding module 9040. A description will be given of operationof each module of the broadcast signal reception apparatus.

The synchronization & demodulation module 9000 may receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the broadcast signal receptionapparatus, and carry out demodulation corresponding to a reverseprocedure of a procedure performed by the broadcast signal transmissionapparatus.

The frame parsing module 9010 may parse input signal frames and extractdata through which a service selected by a user is transmitted. If thebroadcast signal transmission apparatus performs interleaving, the frameparsing module 9010 may carry out deinterleaving corresponding to areverse procedure of interleaving. In this case, positions of a signaland data that need to be extracted may be obtained by decoding dataoutput from the signaling decoding module 9040 to restore schedulinginformation generated by the broadcast signal transmission apparatus.

The demapping & decoding module 9020 may convert input signals into bitdomain data and then deinterleave the same as necessary. The demapping &decoding module 9020 may perform demapping of mapping applied fortransmission efficiency and correct an error generated on a transmissionchannel through decoding. In this case, the demapping & decoding module9020 may obtain transmission parameters necessary for demapping anddecoding by decoding data output from the signaling decoding module9040.

The output processor 9030 may perform reverse procedures of variouscompression/signal processing procedures which are applied by thebroadcast signal transmission apparatus to improve transmissionefficiency. In this case, the output processor 9030 may acquirenecessary control information from data output from the signalingdecoding module 9040. An output of the output processor 9030 correspondsto a signal input to the broadcast signal transmission apparatus and maybe MPEG-TSs, IP streams (v4 or v6) and generic streams.

The signaling decoding module 9040 may obtain PLS information from asignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9010, the demapping & decodingmodule 9020 and the output processor 9030 may execute functions thereofusing data output from the signaling decoding module 9040.

A frame according to an embodiment of the present invention is furtherdivided into a number of OFDM symbols and a preamble. As shown in (d),the frame includes a preamble, one or more frame signaling symbols(FSSs), normal data symbols and a frame edge symbol (FES).

The preamble is a special symbol that enables fast futurecast UTB systemsignal detection and provides a set of basic transmission parameters forefficient transmission and reception of a signal. Details of thepreamble will be described later.

A main purpose of the FSS is to carry PLS data. For fast synchronizationand channel estimation, and hence fast decoding of PLS data, the FSS hasa dense pilot pattern than a normal data symbol. The FES has exactly thesame pilots as the FSS, which enables frequency-only interpolationwithin the FES and temporal interpolation, without extrapolation, forsymbols immediately preceding the FES.

FIG. 23 illustrates a signaling hierarchy structure of a frame accordingto an embodiment of the present invention.

FIG. 23 illustrates the signaling hierarchy structure, which is splitinto three main parts corresponding to preamble signaling data 11000,PLS1 data 11010 and PLS2 data 11020. A purpose of a preamble, which iscarried by a preamble symbol in every frame, is to indicate atransmission type and basic transmission parameters of the frame. PLS1enables the receiver to access and decode the PLS2 data, which containsthe parameters to access a DP of interest. PLS2 is carried in everyframe and split into two main parts corresponding to PLS2-STAT data andPLS2-DYN data. Static and dynamic portions of PLS2 data are followed bypadding, if necessary.

Preamble signaling data according to an embodiment of the presentinvention carries 21 bits of information that are needed to enable thereceiver to access PLS data and trace DPs within the frame structure.Details of the preamble signaling data are as follows.

FFT_SIZE: This 2-bit field indicates an FFT size of a current framewithin a frame group as described in the following Table 1.

TABLE 1 Value FFT size 00  8K FFT 01 16K FFT 10 32K FFT 11 Reserved

GI_FRACTION: This 3-bit field indicates a guard interval fraction valuein a current superframe as described in the following Table 2.

TABLE 2 Value GI_FRACTION 000 1/5  001 1/10 010 1/20 011 1/40 100 1/80101  1/160 110 to 111 Reserved

EAC_FLAG: This 1-bit field indicates whether the EAC is provided in acurrent frame. If this field is set to ‘1’, an emergency alert service(EAS) is provided in the current frame. If this field set to ‘0’, theEAS is not carried in the current frame. This field may be switcheddynamically within a superframe.

PILOT_MODE: This 1-bit field indicates whether a pilot mode is a mobilemode or a fixed mode for a current frame in a current frame group. Ifthis field is set to ‘0’, the mobile pilot mode is used. If the field isset to ‘1’, the fixed pilot mode is used.

PAPR_FLAG: This 1-bit field indicates whether PAPR reduction is used fora current frame in a current frame group. If this field is set to avalue of ‘1’, tone reservation is used for PAPR reduction. If this fieldis set to a value of ‘0’, PAPR reduction is not used.

RESERVED: This 7-bit field is reserved for future use.

FIG. 24 illustrates PLS1 data according to an embodiment of the presentinvention.

PLS1 data provides basic transmission parameters including parametersrequired to enable reception and decoding of PLS2. As mentioned above,the PLS1 data remain unchanged for the entire duration of one framegroup. A detailed definition of the signaling fields of the PLS1 data isas follows.

PREAMBLE_DATA: This 20-bit field is a copy of preamble signaling dataexcluding EAC_FLAG.

NUM_FRAME_FRU: This 2-bit field indicates the number of the frames perFRU.

PAYLOAD_TYPE: This 3-bit field indicates a format of payload datacarried in a frame group. PAYLOAD_TYPE is signaled as shown in Table 3.

TABLE 3 Value Payload type 1XX TS is transmitted. X1X IP stream istransmitted. XX1 GS is transmitted.

NUM_FSS: This 2-bit field indicates the number of FSSs in a currentframe.

SYSTEM_VERSION: This 8-bit field indicates a version of a transmittedsignal format. SYSTEM_VERSION is divided into two 4-bit fields: a majorversion and a minor version.

Major version: The MSB corresponding to four bits of the SYSTEM_VERSIONfield indicates major version information. A change in the major versionfield indicates a non-backward-compatible change. A default value is‘0000’. For a version described in this standard, a value is set to‘0000’.

Minor version: The LSB corresponding to four bits of SYSTEM_VERSIONfield indicates minor version information. A change in the minor versionfield is backwards compatible.

CELL_ID: This is a 16-bit field which uniquely identifies a geographiccell in an ATSC network. An ATSC cell coverage area may include one ormore frequencies depending on the number of frequencies used perfuturecast UTB system. If a value of CELL_ID is not known orunspecified, this field is set to ‘0’.

NETWORK_ID: This is a 16-bit field which uniquely identifies a currentATSC network.

SYSTEM_ID: This 16-bit field uniquely identifies the futurecast UTBsystem within the ATSC network. The futurecast UTB system is aterrestrial broadcast system whose input is one or more input streams(TS, IP, GS) and whose output is an RF signal. The futurecast UTB systemcarries one or more PHY profiles and FEF, if any. The same futurecastUTB system may carry different input streams and use different RFs indifferent geographical areas, allowing local service insertion. Theframe structure and scheduling are controlled in one place and areidentical for all transmissions within the futurecast UTB system. One ormore futurecast UTB systems may have the same SYSTEM_ID meaning thatthey all have the same physical layer structure and configuration.

The following loop includes FRU_PHY_PROFILE, FRU_FRAME_LENGTH,FRU_GI_FRACTION, and RESERVED which are used to indicate an FRUconfiguration and a length of each frame type. A loop size is fixed sothat four PHY profiles (including an FEF) are signaled within the FRU.If NUM_FRAME_FRU is less than 4, unused fields are filled with zeros.

FRU_PHY_PROFILE: This 3-bit field indicates a PHY profile type of an(i+1)th (i is a loop index) frame of an associated FRU. This field usesthe same signaling format as shown in Table 8.

FRU_FRAME_LENGTH: This 2-bit field indicates a length of an (i+1)thframe of an associated FRU. Using FRU_FRAME_LENGTH together withFRU_GI_FRACTION, an exact value of a frame duration may be obtained.

FRU_GI_FRACTION: This 3-bit field indicates a guard interval fractionvalue of an (i+1)th frame of an associated FRU. FRU_GI_FRACTION issignaled according to Table 7.

RESERVED: This 4-bit field is reserved for future use.

The following fields provide parameters for decoding the PLS2 data.

PLS2_FEC_TYPE: This 2-bit field indicates an FEC type used by PLS2protection. The FEC type is signaled according to Table 4. Details ofLDPC codes will be described later.

TABLE 4 Content PLS2 FEC type 00 4K-1/4 and 7K-3/10 LDPC codes 01 to 11Reserved

PLS2_MOD: This 3-bit field indicates a modulation type used by PLS2. Themodulation type is signaled according to Table 5.

TABLE 5 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16 011 NUQ-64 100 to111 Reserved

PLS2_SIZE_CELL: This 15-bit field indicates C_(total_partial_block), asize (specified as the number of QAM cells) of the collection of fullcoded blocks for PLS2 that is carried in a current frame group. Thisvalue is constant during the entire duration of the current frame group.

PLS2_STAT_SIZE_BIT: This 14-bit field indicates a size, in bits, ofPLS2-STAT for a current frame group. This value is constant during theentire duration of the current frame group.

PLS2_DYN_SIZE_BIT: This 14-bit field indicates a size, in bits, ofPLS2-DYN for a current frame group. This value is constant during theentire duration of the current frame group.

PLS2_REP_FLAG: This 1-bit flag indicates whether a PLS2 repetition modeis used in a current frame group. When this field is set to a value of‘1’, the PLS2 repetition mode is activated. When this field is set to avalue of ‘0’, the PLS2 repetition mode is deactivated.

PLS2_REP_SIZE_CELL: This 15-bit field indicates C_(total_partial_block),a size (specified as the number of QAM cells) of the collection ofpartial coded blocks for PLS2 carried in every frame of a current framegroup, when PLS2 repetition is used. If repetition is not used, a valueof this field is equal to 0. This value is constant during the entireduration of the current frame group.

PLS2_NEXT_FEC_TYPE: This 2-bit field indicates an FEC type used for PLS2that is carried in every frame of a next frame group. The FEC type issignaled according to Table 10.

PLS2_NEXT_MOD: This 3-bit field indicates a modulation type used forPLS2 that is carried in every frame of a next frame group. Themodulation type is signaled according to Table 11.

PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the PLS2repetition mode is used in a next frame group. When this field is set toa value of ‘1’, the PLS2 repetition mode is activated. When this fieldis set to a value of ‘0’, the PLS2 repetition mode is deactivated.

PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicatesC_(total_full_block), a size (specified as the number of QAM cells) ofthe collection of full coded blocks for PLS2 that is carried in everyframe of a next frame group, when PLS2 repetition is used. If repetitionis not used in the next frame group, a value of this field is equal to0. This value is constant during the entire duration of a current framegroup.

PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates a size, inbits, of PLS2-STAT for a next frame group. This value is constant in acurrent frame group.

PLS2_NEXT_REP_DYN_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-DYN for a next frame group. This value is constant ina current frame group.

PLS2_AP_MODE: This 2-bit field indicates whether additional parity isprovided for PLS2 in a current frame group. This value is constantduring the entire duration of the current frame group. Table 6 belowprovides values of this field. When this field is set to a value of‘00’, additional parity is not used for the PLS2 in the current framegroup.

TABLE 6 Value PLS2-AP mode 00 AP is not provided 01 AP1 mode 10 to 11Reserved

PLS2_AP_SIZE_CELL: This 15-bit field indicates a size (specified as thenumber of QAM cells) of additional parity bits of PLS2. This value isconstant during the entire duration of a current frame group.

PLS2_NEXT_AP_MODE: This 2-bit field indicates whether additional parityis provided for PLS2 signaling in every frame of a next frame group.This value is constant during the entire duration of a current framegroup. Table 12 defines values of this field.

PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates a size (specified asthe number of QAM cells) of additional parity bits of PLS2 in everyframe of a next frame group. This value is constant during the entireduration of a current frame group.

RESERVED: This 32-bit field is reserved for future use.

CRC_32: A 32-bit error detection code, which is applied to all PLS1signaling.

FIG. 25 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 25 illustrates PLS2-STAT data of the PLS2 data. The PLS2-STAT datais the same within a frame group, while PLS2-DYN data providesinformation that is specific for a current frame.

Details of fields of the PLS2-STAT data are described below.

FIC_FLAG: This 1-bit field indicates whether the FIC is used in acurrent frame group. If this field is set to ‘1’, the FIC is provided inthe current frame. If this field set to ‘0’, the FIC is not carried inthe current frame. This value is constant during the entire duration ofa current frame group.

AUX_FLAG: This 1-bit field indicates whether an auxiliary stream is usedin a current frame group. If this field is set to ‘1’, the auxiliarystream is provided in a current frame. If this field set to ‘0’, theauxiliary stream is not carried in the current frame. This value isconstant during the entire duration of current frame group.

NUM_DP: This 6-bit field indicates the number of DPs carried within acurrent frame. A value of this field ranges from 1 to 64, and the numberof DPs is NUM_DP+1.

DP_ID: This 6-bit field identifies uniquely a DP within a PHY profile.

DP_TYPE: This 3-bit field indicates a type ofa DP. This is signaledaccording to the following Table 7.

TABLE 7 Value DP Type 000 DP Type 1 001 DP Type 2 010 to 111 Reserved

DP_GROUP_ID: This 8-bit field identifies a DP group with which a currentDP is associated. This may be used by the receiver to access DPs ofservice components associated with a particular service having the sameDP_GROUP_ID.

BASE_DP_ID: This 6-bit field indicates a DP carrying service signalingdata (such as PSI/SI) used in a management layer. The DP indicated byBASE_DP_ID may be either a normal DP carrying the service signaling dataalong with service data or a dedicated DP carrying only the servicesignaling data.

DP_FEC_TYPE: This 2-bit field indicates an FEC type used by anassociated DP. The FEC type is signaled according to the following Table8.

TABLE 8 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10 to 11 Reserved

DP_COD: This 4-bit field indicates a code rate used by an associated DP.The code rate is signaled according to the following Table 9.

TABLE 9 Value Code rate 0000 5/15 0001 6/15 0010 7/15 0011 8/15 01009/15 0101 10/15  0110 11/15  0111 12/15  1000 13/15  1001 to 1111Reserved

DP_MOD: This 4-bit field indicates modulation used by an associated DP.Th modulation is signaled according to the following Table 10.

TABLE 10 Value Modulation 0000 QPSK 0001 QAM-16 0010 NUQ-64 0011 NUQ-2560100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111 NUC-256 1000 NUC-1024 1001 to1111 Reserved

DP_SSD_FLAG: This 1-bit field indicates whether an SSD mode is used inan associated DP. If this field is set to a value of ‘1’, SSD is used.If this field is set to a value of ‘0’, SSD is not used.

The following field appears only if PHY_PROFILE is equal to ‘010’, whichindicates the advanced profile:

DP_MIMO: This 3-bit field indicates which type of MIMO encoding processis applied to an associated DP. A type of MIMO encoding process issignaled according to the following Table 11.

TABLE 11 Value MIMO encoding 000 FR-SM 001 FRFD-SM 010 to 111 Reserved

DP_TI_TYPE: This 1-bit field indicates a type of time interleaving. Avalue of ‘0’ indicates that one TI group corresponds to one frame andcontains one or more TI blocks. A value of ‘1’ indicates that one TIgroup is carried in more than one frame and contains only one TI block.

DP_TI_LENGTH: The use of this 2-bit field (allowed values are only 1, 2,4, and 8) is determined by values set within the DP_TI_TYPE field asfollows.

If DP_TI_TYPE is set to a value of ‘1’, this field indicates PI, thenumber of frames to which each TI group is mapped, and one TI block ispresent per TI group (NTI=1). Allowed values of PI with the 2-bit fieldare defined in Table 12 below.

If DP_TI_TYPE is set to a value of ‘0’, this field indicates the numberof TI blocks NTI per TI group, and one TI group is present per frame(PI=1). Allowed values of PI with the 2-bit field are defined in thefollowing Table 12.

TABLE 12 2-bit field P_(I) N_(TI) 00 1 1 01 2 2 10 4 3 11 8 4

DP_FRAME_INTERVAL: This 2-bit field indicates a frame interval (IJUMP)within a frame group for an associated DP and allowed values are 1, 2,4, and 8 (the corresponding 2-bit field is ‘00’, ‘01’, ‘10’, or ‘11’,respectively). For DPs that do not appear every frame of the framegroup, a value of this field is equal to an interval between successiveframes. For example, if a DP appears on frames 1, 5, 9, 13, etc., thisfield is set to a value of ‘4’. For DPs that appear in every frame, thisfield is set to a value of ‘1’.

DP_TI_BYPASS: This 1-bit field determines availability of the timeinterleaver 5050. If time interleaving is not used for a DP, a value ofthis field is set to ‘1’. If time interleaving is used, the value is setto ‘0’.

DP_FIRST_FRAME_IDX: This 5-bit field indicates an index of a first frameof a superframe in which a current DP occurs. A value ofDP_FIRST_FRAME_IDX ranges from 0 to 31.

DP_NUM_BLOCK_MAX: This 10-bit field indicates a maximum value ofDP_NUM_BLOCKS for this DP. A value of this field has the same range asDP_NUM_BLOCKS.

DP_PAYLOAD_TYPE: This 2-bit field indicates a type of payload datacarried by a given DP. DP_PAYLOAD_TYPE is signaled according to thefollowing Table 13.

TABLE 13 Value Payload type 00 TS 01 IP 10 GS 11 Reserved

DP_INBAND_MODE: This 2-bit field indicates whether a current DP carriesin-band signaling information. An in-band signaling type is signaledaccording to the following Table 14.

TABLE 14 Value In-band mode 00 In-band signaling is not carried. 01INBAND-PLS is carried 10 INBAND-ISSY is carried 11 INBAND-PLS andINBAND-ISSY are carried

DP_PROTOCOL_TYPE: This 2-bit field indicates a protocol type of apayload carried by a given DP. The protocol type is signaled accordingto Table 15 below when input payload types are selected.

TABLE 15 If DP_PAY- If DP_PAY- If DP_PAY- LOAD_TYPE LOAD_TYPE LOAD_TYPEValue is TS is IP is GS 00 MPEG2-TS IPv4 (Note) 01 Reserved IPv6Reserved 10 Reserved Reserved Reserved 11 Reserved Reserved Reserved

DP_CRC_MODE: This 2-bit field indicates whether CRC encoding is used inan input formatting block. A CRC mode is signaled according to thefollowing Table 16.

TABLE 16 Value CRC mode 00 Not used 01 CRC-8 10 CRC-16 11 CRC-32

DNP_MODE: This 2-bit field indicates a null-packet deletion mode used byan associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). DNP_MODE issignaled according to Table 17 below. If DP_PAYLOAD_TYPE is not TS(‘00’), DNP_MODE is set to a value of ‘00’.

TABLE 17 Value Null-packet deletion mode 00 Not used 01 DNP-NORMAL 10DNP-OFFSET 11 Reserved

ISSY_MODE: This 2-bit field indicates an ISSY mode used by an associatedDP when DP_PAYLOAD_TYPE is set to TS (‘00’). ISSY_MODE is signaledaccording to Table 18 below. If DP_PAYLOAD_TYPE is not TS (‘00’),ISSY_MODE is set to the value of ‘00’.

TABLE 18 Value ISSY mode 00 Not used 01 ISSY-UP 10 ISSY-BBF 11 Reserved

HC_MODE_TS: This 2-bit field indicates a TS header compression mode usedby an associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). HC_MODE_TSis signaled according to the following Table 19.

TABLE 19 Value Header compression mode 00 HC_MODE_TS 1 01 HC_MODE_TS 210 HC_MODE_TS 3 11 HC_MODE_TS 4

HC_MODE_IP: This 2-bit field indicates an IP header compression modewhen DP_PAYLOAD_TYPE is set to 1P (‘01’). HC_MODE_IP is signaledaccording to the following Table 20.

TABLE 20 Value Header compression mode 00 No compression 01 HC_MODE_IP 110 to 11 Reserved

PID: This 13-bit field indicates the PID number for TS headercompression when DP_PAYLOAD_TYPE is set to TS (‘00’) and HC_MODE_TS isset to ‘01’ or ‘10’.

RESERVED: This 8-bit field is reserved for future use.

The following fields appear only if FIC_FLAG is equal to ‘1’.

FIC_VERSION: This 8-bit field indicates the version number of the FIC.

FIC_LENGTH_BYTE: This 13-bit field indicates the length, in bytes, ofthe FIC.

RESERVED: This 8-bit field is reserved for future use.

The following fields appear only if AUX_FLAG is equal to ‘1’.

NUM_AUX: This 4-bit field indicates the number of auxiliary streams.Zero means no auxiliary stream is used.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use.

AUX_STREAM_TYPE: This 4-bit is reserved for future use for indicating atype of a current auxiliary stream.

AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future use forsignaling auxiliary streams.

FIG. 26 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 26 illustrates PLS2-DYN data of the PLS2 data. Values of thePLS2-DYN data may change during the duration of one frame group whilesizes of fields remain constant.

Details of fields of the PLS2-DYN data are as below.

FRAME_INDEX: This 5-bit field indicates a frame index of a current framewithin a superframe. An index of a first frame of the superframe is setto ‘0’.

PLS_CHANGE_COUNTER: This 4-bit field indicates the number of superframesbefore a configuration changes. A next superframe with changes in theconfiguration is indicated by a value signaled within this field. Ifthis field is set to a value of ‘0000’, it means that no scheduledchange is foreseen. For example, a value of ‘1’ indicates that there isa change in the next superframe.

FIC_CHANGE_COUNTER: This 4-bit field indicates the number of superframesbefore a configuration (i.e., content of the FIC) changes. A nextsuperframe with changes in the configuration is indicated by a valuesignaled within this field. If this field is set to a value of ‘0000’,it means that no scheduled change is foreseen. For example, a value of‘0001’ indicates that there is a change in the next superframe.

RESERVED: This 16-bit field is reserved for future use.

The following fields appear in a loop over NUM_DP, which describeparameters associated with a DP carried in a current frame.

DP_ID: This 6-bit field uniquely indicates a DP within a PHY profile.

DP_START: This 15-bit (or 13-bit) field indicates a start position ofthe first of the DPs using a DPU addressing scheme. The DP_START fieldhas differing length according to the PHY profile and FFT size as shownin the following Table 21.

TABLE 21 DP_START field size PHY profile 64K 16K Base 13 bits 15 bitsHandheld — 13 bits Advanced 13 bits 15 its 

DP_NUM_BLOCK: This 10-bit field indicates the number of FEC blocks in acurrent TI group for a current DP. A value of DP_NUM_BLOCK ranges from 0to 1023.

RESERVED: This 8-bit field is reserved for future use.

The following fields indicate FIC parameters associated with the EAC.

EAC_FLAG: This 1-bit field indicates the presence of the EAC in acurrent frame. This bit is the same value as EAC_FLAG in a preamble.

EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates a version number ofa wake-up indication.

If the EAC_FLAG field is equal to ‘1’, the following 12 bits areallocated to EAC_LENGTH_BYTE. If the EAC_FLAG field is equal to ‘0’, thefollowing 12 bits are allocated to EAC_COUNTER.

EAC_LENGTH_BYTE: This 12-bit field indicates a length, in bytes, of theEAC.

EAC_COUNTER: This 12-bit field indicates the number of frames before aframe where the EAC arrives.

The following fields appear only if the AUX_FLAG field is equal to ‘1’.

AUX_PRIVATE_DYN: This 48-bit field is reserved for future use forsignaling auxiliary streams. A meaning of this field depends on a valueof AUX_STREAM_TYPE in a configurable PLS2-STAT.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS2.

FIG. 27 illustrates a logical structure of a frame according to anembodiment of the present invention.

As above mentioned, the PLS, EAC, FIC, DPs, auxiliary streams and dummycells are mapped to the active carriers of OFDM symbols in a frame. PLS1and PLS2 are first mapped to one or more FSSs. Thereafter, EAC cells, ifany, are mapped to an immediately following PLS field, followed next byFIC cells, if any. The DPs are mapped next after the PLS or after theEAC or the FIC, if any. Type 1 DPs are mapped first and Type 2 DPs aremapped next. Details of types of the DPs will be described later. Insome cases, DPs may carry some special data for EAS or service signalingdata. The auxiliary streams or streams, if any, follow the DPs, which inturn are followed by dummy cells. When the PLS, EAC, FIC, DPs, auxiliarystreams and dummy data cells are mapped all together in the abovementioned order, i.e. the PLS, EAC, FIC, DPs, auxiliary streams anddummy data cells, cell capacity in the frame is exactly filled.

FIG. 28 illustrates PLS mapping according to an embodiment of thepresent invention.

PLS cells are mapped to active carriers of FSS(s). Depending on thenumber of cells occupied by PLS, one or more symbols are designated asFSS(s), and the number of FSS(s) NFSS is signaled by NUM_FSS in PLS1.The FSS is a special symbol for carrying PLS cells. Since robustness andlatency are critical issues in the PLS, the FSS(s) have higher pilotdensity, allowing fast synchronization and frequency-only interpolationwithin the FSS.

PLS cells are mapped to active carriers of the FSS(s) in a top-downmanner as shown in the figure. PLS1 cells are mapped first from a firstcell of a first FSS in increasing order of cell index. PLS2 cells followimmediately after a last cell of PLS1 and mapping continues downwarduntil a last cell index of the first FSS. If the total number ofrequired PLS cells exceeds the number of active carriers of one FSS,mapping proceeds to a next FSS and continues in exactly the same manneras the first FSS.

After PLS mapping is completed, DPs are carried next. If an EAC, an FICor both are present in a current frame, the EAC and the FIC are placedbetween the PLS and “normal” DPs.

Hereinafter, description will be given of encoding an FEC structureaccording to an embodiment of the present invention. As above mentioned,the data FEC encoder may perform FEC encoding on an input BBF togenerate an FECBLOCK procedure using outer coding (BCH), and innercoding (LDPC). The illustrated FEC structure corresponds to theFECBLOCK. In addition, the FECBLOCK and the FEC structure have samevalue corresponding to a length of an LDPC codeword.

As described above, BCH encoding is applied to each BBF (K_(bch) bits),and then LDPC encoding is applied to BCH-encoded BBF (K_(ldpc)bits=N_(bch) bits).

A value of N_(ldpc) is either 64,800 bits (long FECBLOCK) or 16,200 bits(short FECBLOCK).

Table 22 and Table 23 below show FEC encoding parameters for the longFECBLOCK and the short FECBLOCK, respectively.

TABLE 22 LDPC BCH error rate N_(ldpc) K_(ldpc) K_(bch) correctioncapability N_(bch) − K_(bch) 5/15 64800 21600 21408 12 192 6/15 2592025728 7/15 30240 30048 8/15 34560 34368 9/15 38880 38688 10/15  4320043008 11/15  47520 47328 12/15  51840 51648 13/15  56160 55968

TABLE 23 LDPC BCH error rate N_(ldpc) K_(ldpc) K_(bch) correctioncapability N_(bch) − K_(bch) 5/15 16200 5400 5232 12 168 6/15 6480 63127/15 7560 7392 8/15 8640 8472 9/15 9720 9552 10/15  10800 10632 11/15 11880 11712 12/15  12960 12792 13/15  14040 13872

Detailed operations of BCH encoding and LDPC encoding are as below.

A 12-error correcting BCH code is used for outer encoding of the BBF. ABCH generator polynomial for the short FECBLOCK and the long FECBLOCKare obtained by multiplying all polynomials together.

LDPC code is used to encode an output of outer BCH encoding. To generatea completed B_(ldpc) (FECBLOCK), P_(ldpc) (parity bits) is encodedsystematically from each I_(ldpc) (BCH—encoded BBF), and appended toI_(ldpc). The completed B_(ldpc) (FECBLOCK) is expressed by thefollowing Equation.B _(ldpc)=[I _(ldpc) P _(ldpc)]=[i ₀ ,i ₁ , . . . ,p ₀ ,p ₁ , . . . ,p_(N) _(ldpc) _(−K) _(ldpc) ⁻¹]  [Equation 2]

Parameters for the long FECBLOCK and the short FECBLOCK are given in theabove Tables 22 and 23, respectively.

A detailed procedure to calculate N_(ldpc)−K_(ldpc) parity bits for thelong FECBLOCK, is as follows.

1) Initialize the parity bitsp ₀ =p ₁ =p ₂ = . . . =p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹=0  [Equation 3]

2) Accumulate a first information bit—i₀, at a parity bit addressspecified in a first row of addresses of a parity check matrix. Detailsof the addresses of the parity check matrix will be described later. Forexample, for the rate of 13/15,p ₉₈₃ =p ₉₈₃ ⊕i ₀ p ₂₈₁₅ =p ₂₈₁₅ ⊕i ₀p ₄₇₃₇ =p ₄₈₃₇ ⊕i ₀ p ₄₉₈₉ =p ₄₉₈₉ ⊕i ₀p ₆₁₃₈ =p ₆₁₃₈ ⊕i ₀ p ₆₄₅₈ =p ₆₄₅₈ ⊕i ₀p ₆₉₂₁ =p ₆₉₂₁ ⊕i ₀ p ₆₉₇₄ =p ₆₉₇₄ ⊕i ₀p ₇₅₇₂ =p ₇₅₇₂ ⊕i ₀ p ₈₂₆₀ =p ₈₂₆₀ ⊕i ₀p ₈₄₉₆ =p ₈₄₉₆ ⊕i ₀  [equation 4]

3) For the next 359 information bits, i_(s), s=1, 2, . . . , 359,accumulate is at parity bit addresses using following Equation.{x+(s mod 360)×Q _(ldpc)} mod(N _(ldpc) −K _(ldpc))  [Equation 5]

Here, x denotes an address of a parity bit accumulator corresponding toa first bit i₀, and Q_(ldpc) is a code rate dependent constant specifiedin the addresses of the parity check matrix. Continuing with theexample, Q_(ldpc)=24 for the rate of 13/15, so for an information biti1, the following operations are performed.p ₁₀₀₇ =p ₁₀₀₇ ⊕i ₁ p ₂₈₃₉ =p ₂₈₃₉ ⊕i ₁p ₄₈₆₁ =p ₄₈₆₁ ⊕i ₁ p ₅₀₁₃ =P ₅₀₁₃ ⊕i ₁p ₆₁₆₂ =P ₆₁₆₂ ⊕i ₁ p ₆₄₈₂ =p ₆₄₈₂ ⊕i ₁p ₆₉₄₅ =P ₆₉₄₅ ⊕i ₁ p ₆₉₉₈ =P ₆₉₉₈ ⊕i ₁p ₇₅₉₆ =P ₇₅₉₆ ⊕i ₁ p ₈₂₈₄ =P ₈₂₈₄ ⊕i ₁p ₈₅₂₀ =P ₈₅₂₀ ⊕i ₁  [Equation 6]

4) For a 361th information bit i₃₆₀, an address of the parity bitaccumulator is given in a second row of the addresses of the paritycheck matrix. In a similar manner, addresses of the parity bitaccumulator for the following 359 information bits is, s=361, 362, . . ., 719 are obtained using Equation 6, where x denotes an address of theparity bit accumulator corresponding to the information bit i₃₆₀, i.e.,an entry in the second row of the addresses of the parity check matrix.

5) In a similar manner, for every group of 360 new information bits, anew row from the addresses of the parity check matrix is used to findthe address of the parity bit accumulator.

After all of the information bits are exhausted, a final parity bit isobtained as below.

6) Sequentially perform the following operations starting with i=1.p _(i) =p _(i) ⊕p _(i-1) ,i=1,2, . . . ,N _(ldpc) −K_(ldpc)−1  [Equation 7]

Here, final content of p_(i) (i=0, 1, . . . , N_(ldpc)−K_(ldpc)−1) isequal to a parity bit p_(i).

TABLE 24 Code rate Q_(ldpc) 5/15 120 6/15 108 7/15 96 8/15 84 9/15 7210/15  60 11/15  48 12/15  36 13/15  24

This LDPC encoding procedure for the short FECBLOCK is in accordancewith t LDPC encoding procedure for the long FECBLOCK, except that Table24 is replaced with Table 25, and the addresses of the parity checkmatrix for the long FECBLOCK are replaced with the addresses of theparity check matrix for the short FECBLOCK.

TABLE 25 Code rate Q_(ldpc) 5/15 30 6/15 27 7/15 24 8/15 21 9/15 1810/15  15 11/15  12 12/15  9 13/15  6

FIG. 29 illustrates time interleaving according to an embodiment of thepresent invention.

(a) to (c) show examples of a TI mode.

A time interleaver operates at the DP level. Parameters of timeinterleaving (TI) may be set differently for each DP.

The following parameters, which appear in part of the PLS2-STAT data,configure the TI.

DP_TI_TYPE (allowed values: 0 or 1): This parameter represents the TImode. The value of ‘0’ indicates a mode with multiple TI blocks (morethan one TI block) per TI group. In this case, one TI group is directlymapped to one frame (no inter-frame interleaving). The value of ‘1’indicates a mode with only one TI block per TI group. In this case, theTI block may be spread over more than one frame (inter-frameinterleaving).

DP_TI_LENGTH: If DP_TI_TYPE=‘0’, this parameter is the number of TIblocks NTI per TI group. For DP_TI_TYPE=‘1’, this parameter is thenumber of frames PI spread from one TI group.

DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): This parameter representsthe maximum number of XFECBLOCKs per TI group.

DP_FRAME_INTERVAL (allowed values: 1, 2, 4, and 8): This parameterrepresents the number of the frames I_(JUMP) between two successiveframes carrying the same DP of a given PHY profile.

DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving is not usedfor a DP, this parameter is set to ‘1’. This parameter is set to ‘0’ iftime interleaving is used.

Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN data is usedto represent the number of XFECBLOCKs carried by one TI group of the DP.

When time interleaving is not used for a DP, the following TI group,time interleaving operation, and TI mode are not considered. However,the delay compensation block for the dynamic configuration informationfrom the scheduler may still be required. In each DP, the XFECBLOCKsreceived from SSD/MIMO encoding are grouped into TI groups. That is,each TI group is a set of an integer number of XFECBLOCKs and contains adynamically variable number of XFECBLOCKs. The number of XFECBLOCKs inthe TI group of index n is denoted by N_(xBLOCK_Group)(n) and issignaled as DP_NUM_BLOCK in the PLS2-DYN data. Note thatN_(xBLOCK_Group)(n) may vary from a minimum value of 0 to a maximumvalue of N_(xBLOCK_Group_MAX) (corresponding to DP_NUM_BLOCK_MAX), thelargest value of which is 1023.

Each TI group is either mapped directly to one frame or spread over PIframes. Each TI group is also divided into more than one TI block(N_(TI)), where each TI block corresponds to one usage of a timeinterleaver memory. The TI blocks within the TI group may containslightly different numbers of XFECBLOCKs. If the TI group is dividedinto multiple TI blocks, the TI group is directly mapped to only oneframe. There are three options for time interleaving (except an extraoption of skipping time interleaving) as shown in the following Table26.

TABLE 26 Modes Descriptions Option 1 Each TI group contains one TI blockand is mapped directly to one frame as shown in (a). This option issignaled in PLS2- STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH = ‘1’(N_(TI) = 1). Option 2 Each TI group contains one TI block and is mappedto more than one frame. (b) shows an example, where one TI group ismapped to two frames, i.e., DP_TI_LENGTH = ‘2’ (P_(I) = 2) andDP_FRAME_INTERVAL (I_(JUMP) = 2). This provides greater time diversityfor low data-rate services. This option is signaled in PLS2-STAT byDP_TI_TYPE = ‘1’. Option 3 Each TI group is divided into multiple TIblocks and is mapped directly to one frame as shown in (c). Each TIblock may use a full TI memory so as to provide a maximum bit-rate for aDP. This option is signaled in PLS2-STAT by DP_TI_TYPE = ‘0’ andDP_TI_LENGTH = N_(TI), while P_(I) = 1.

Typically, the time interleaver may also function as a buffer for DPdata prior to a process of frame building. This is achieved by means oftwo memory banks for each DP. A first TI block is written to a firstbank. A second TI block is written to a second bank while the first bankis being read from and so on.

The TI is a twisted row-column block interleaver. For an sth TI block ofan nth TI group, the number of rows N_(r) of a TI memory is equal to thenumber of cells Ncells, i.e., N_(r)=N_(cells) while the number ofcolumns N_(c) is equal to the number N_(xBLOCK_TI)(n,s).

FIG. 30 illustrates a basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 30(a) shows a write operation in the time interleaver and FIG.30(b) shows a read operation in the time interleaver. A first XFECBLOCKis written column-wise into a first column of a TI memory, and a secondXFECBLOCK is written into a next column, and so on as shown in (a).Then, in an interleaving array, cells are read diagonal-wise. Duringdiagonal-wise reading from a first row (rightwards along a row beginningwith a left-most column) to a last row, Nr cells are read out as shownin (b). In detail, assuming Z_(n,s,i)(i=0, . . . , N_(r)N_(c)) as a TImemory cell position to be read sequentially, a reading process in suchan interleaving array is performed by calculating a row index R_(n,s,i),a column index C_(n,s,i), and an associated twisting parameter T_(n,s,i)as in the following Equation.

$\begin{matrix}{{{GENERATE}\left( {R_{n,s,i},C_{n,s,i}} \right)} = \left\{ {{R_{n,s,i} = {{mod}\left( {i,N_{r}} \right)}},{T_{n,s,i} = {{mod}\left( {{S_{shift} \times R_{n,s,i}},N_{c}} \right)}},{C_{n,s,i} = {{mod}\left( {{T_{n,s,i} + \left\lfloor \frac{i}{N_{r}} \right\rfloor},N_{c}} \right)}}} \right\}} & \left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack\end{matrix}$

Here, S_(shift) is a common shift value for a diagonal-wise readingprocess regardless of N_(xBLOCK_TI)(n,s), and the shift value isdetermined by N_(xBLOCK_TI_MAX) given in PLS2-STAT as in the followingEquation.

          [Equation  9] ${for}\left\{ {\begin{matrix}{{N_{{{xBLOCK}\_{TI}}{\_{MAX}}}^{\prime} = {N_{{{xBLOCK}\_{TI}}{\_{MAX}}} + 1}},} & {{{if}\mspace{14mu} N_{{{xBLOCK}\_{TI}}{\_{MAX}}}{{mod}2}} = 0} \\{{N_{{{xBLOCK}\_{TI}}{\_{MAX}}}^{\prime} = N_{{{xBLOCK}\_{TI}}{\_{MAX}}}},} & {{{if}\mspace{14mu} N_{{{xBLOCK}\_{TI}}{\_{MAX}}}{{mod}2}} = 1}\end{matrix},\mspace{20mu}{S_{shift} = \frac{N_{{{xBLOCK}\_{TI}}{\_{MAX}}}^{\prime} - 1}{2}}} \right.$

As a result, cell positions to be read are calculated by coordinatesZ_(n,s,i)=N_(r)C_(n,s,i)+R_(n,s,i).

FIG. 31 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

More specifically, FIG. 31 illustrates an interleaving array in a TImemory for each TI group, including virtual XFECBLOCKs whenN_(xBLOCK_TI)(0,0)=3, N_(xBLOCK_TI)(1,0)=6 and N_(xBLOCK_TI)(2,0)=5.

A variable number N_(xBLOCK_TI)(n,s)=N_(r) may be less than or equal toN′_(xBLOCK_TI_MAX). Thus, in order to achieve single-memorydeinterleaving at a receiver side regardless of N_(xBLOCK_TI)(n,s), theinterleaving array for use in the twisted row-column block interleaveris set to a size of N_(r)×N_(c)=N_(cells)×N′_(xBLOCK_TI_MAX) byinserting the virtual XFECBLOCKs into the TI memory and a readingprocess is accomplished as in the following Equation.

[Equation 10] p = 0; for i = 0; i < N_(cells)N_(xBLOCK)_TI_MAX′; i = i +1 {GENERATE(R_(n.s.i), C_(n,s,i)); V_(i) = N_(r)C_(n,s,j) + R_(n,s,j) if V_(i) < N_(cells)N_(xBLOCK)_TI(n,s)  {   Z_(n,s,p) = V_(i); p = p +1;   } }

The number of TI groups is set to 3. An option of the time interleaveris signaled in the PLS2-STAT data by DP_TI_TYPE=‘0’,DP_FRAME_INTERVAL=‘1’, and DP_TI_LENGTH=‘1’, i.e., NTI=1, IJUMP=1, andPI=1. The number of XFECBLOCKs, each of which has Ncells=30 cells, perTI group is signaled in the PLS2-DYN data by NxBLOCK_TI(0,0)=3,NxBLOCK_TI(1,0)=6, and NxBLOCK_TI(2,0)=5, respectively. A maximum numberof XFECBLOCKs is signaled in the PLS2-STAT data by NxBLOCK_Group_MAX,which leads to └_(xBLOCK_Group_MAX)/N_(TI)┘=N_(xBLOCK_TI_MAX)=6

The purpose of the Frequency Interleaver, which operates on datacorresponding to a single OFDM symbol, is to provide frequency diversityby randomly interleaving data cells received from the frame builder. Inorder to get maximum interleaving gain in a single frame, a differentinterleaving-sequence is used for every OFDM symbol pair comprised oftwo sequential OFDM symbols.

Therefore, the frequency interleaver according to the present embodimentmay include an interleaving address generator for generating aninterleaving address for applying corresponding data to a symbol pair.

FIG. 32 illustrates an interleaving address generator including a mainpseudo-random binary sequence (PRBS) generator and a sub-PRBS generatoraccording to each FFT mode according to an embodiment of the presentinvention.

(a) shows the block diagrams of the interleaving-address generator for8K FFT mode, (b) shows the block diagrams of the interleaving-addressgenerator for 16K FFT mode and (c) shows the block diagrams of theinterleaving-address generator for 32K FFT mode.

The interleaving process for the OFDM symbol pair is described asfollows, exploiting a single interleaving-sequence. First, availabledata cells (the output cells from the Cell Mapper) to be interleaved inone OFDM symbol O_(m,l) is defined as O_(m,l)=[x_(m,l,0), . . . ,x_(m,l,p), . . . , x_(m,l,N) _(data) ⁻¹] for l=0, . . . , N_(sym)−1,where xm,l,p is the pth cell of the lth OFDM symbol in the mth frame andN(a, is the number of data cells: N_(data)=C_(FSS) for the framesignaling symbol(s), N_(data)=C_(data) for the normal data, andN_(data)=C_(FES) for the frame edge symbol. In addition, the interleaveddata cells are defined as P_(m,l)=[v_(m,l,0), . . . , v_(m,l,N) _(data)⁻¹] for l=0, . . . , N_(sym)−1.

For the OFDM symbol pair, the interleaved OFDM symbol pair is given byv_(m,l,H) _(l) _((p))=x_(m,l,p), p=0, . . . , N_(data)−1, for the firstOFDM symbol of each pair x_(m,i,p)=v_(m,l,H) _(l) _((p)), p=0, . . . ,N_(data)−1, for the second OFDM symbol of each pair, where H_(l)(p) isthe interleaving address generated by a PRBS generator.

FIG. 33 illustrates a main PRBS used for all FFT modes according to anembodiment of the present invention.

(a) illustrates the main PRBS, and (b) illustrates a parameter Nmax foreach FFT mode.

FIG. 34 illustrates a sub-PRBS used for FFT modes and an interleavingaddress for frequency interleaving according to an embodiment of thepresent invention.

(a) illustrates a sub-PRBS generator, and (b) illustrates aninterleaving address for frequency interleaving. A cyclic shift valueaccording to an embodiment of the present invention may be referred toas a symbol offset.

FIG. 35 illustrates a write operation of a time interleaver according toan embodiment of the present invention.

FIG. 35 illustrates a write operation for two TI groups.

A left block in the figure illustrates a TI memory address array, andright blocks in the figure illustrate a write operation when two virtualFEC blocks and one virtual FEC block are inserted into heads of twocontiguous TI groups, respectively.

Hereinafter, description will be given of a configuration of a timeinterleaver and a time interleaving method using both a convolutionalinterleaver (CI) and a block interleaver (BI) or selectively usingeither the CI or the BI according to a physical layer pipe (PLP) mode. APLP according to an embodiment of the present invention is a physicalpath corresponding to the same concept as that of the above-describedDP, and a name of the PLP may be changed by a designer.

A PLP mode according to an embodiment of the present invention mayinclude a single PLP mode or a multi-PLP mode according to the number ofPLPs processed by a broadcast signal transmitter or a broadcast signaltransmission apparatus. The single PLP mode corresponds to a case inwhich one PLP is processed by the broadcast signal transmissionapparatus. The single PLP mode may be referred to as a single PLP.

The multi-PLP mode corresponds to a case in which one or more PLPs areprocessed by the broadcast signal transmission apparatus. The multi-PLPmode may be referred to as multiple PLPs.

In the present invention, time interleaving in which different timeinterleaving schemes are applied according to PLP modes may be referredto as hybrid time interleaving. Hybrid time interleaving according to anembodiment of the present invention is applied for each PLP (or at eachPLP level) in the multi-PLP mode.

FIG. 36 illustrates an interleaving type applied according to the numberof PLPs in a table.

In a time interleaving according to an embodiment of the presentinvention, an interleaving type may be determined based on a value ofPLP_NUM. PLP_NUM is a signaling field indicating a PLP mode. WhenPLP_NUM has a value of 1, the PLP mode corresponds to a single PLP. Thesingle PLP according to the present embodiment may be applied only to aCI.

When PLP_NUM has a value greater than 1, the PLP mode corresponds tomultiple PLPs. The multiple PLPs according to the present embodiment maybe applied to the CI and a BI. In this case, the CI may performinter-frame interleaving, and the BI may perform intra-frameinterleaving.

FIG. 37 is a block diagram including a first example of a structure of ahybrid time interleaver described above.

The hybrid time interleaver according to the first example may include aBI and a CI. The time interleaver of the present invention may bepositioned between a BICM chain block and a frame builder.

The BICM chain block illustrated in FIGS. 37 and 38 may include theblocks in the processing block 5000 of the BICM block illustrated inFIG. 19 except for the time interleaver 5050. The frame builderillustrated in FIGS. 37 and 38 may perform the same function as that ofthe frame building block 1020 of FIG. 18.

As described in the foregoing, it is possible to determine whether toapply the BI according to the first example of the structure of thehybrid time interleaver depending on values of PLP_NUM. That is, whenPLP_NUM=1, the BI is not applied (BI is turned OFF) and only the CI isapplied. When PLP_NUM>1, both the BI and the CI may be applied (BI isturned ON). A structure and an operation of the CI applied whenPLP_NUM>1 may be the same as or similar to a structure and an operationof the CI applied when PLP_NUM=1.

FIG. 38 is a block diagram including a second example of the structureof the hybrid time interleaver described above.

An operation of each block included in the second example of thestructure of the hybrid time interleaver is the same as the abovedescription in FIG. 20. It is possible to determine whether to apply aBI according to the second example of the structure of the hybrid timeinterleaver depending on values of PLP_NUM. Each block of the hybridtime interleaver according to the second example may perform operationsaccording to embodiments of the present invention. In this instance, anapplied structure and operation of a CI may be different between a caseof PLP_NUM=1 and a case of PLP_NUM>1.

FIG. 39 is a block diagram including a first example of a structure of ahybrid time deinterleaver.

The hybrid time deinterleaver according to the first example may performan operation corresponding to a reverse operation of the hybrid timeinterleaver according to the first example described above. Therefore,the hybrid time deinterleaver according to the first example of FIG. 39may include a convolutional deinterleaver (CDI) and a blockdeinterleaver (BDI).

A structure and an operation of the CDI applied when PLP_NUM>1 may bethe same as or similar to a structure and an operation of the CDIapplied when PLP_NUM=1.

It is possible to determine whether to apply the BDI according to thefirst example of the structure of the hybrid time deinterleaverdepending on values of PLP_NUM. That is, when PLP_NUM=1, the BDI is notapplied (BDI is turned OFF) and only the CDI is applied.

The CDI of the hybrid time deinterleaver may perform inter-framedeinterleaving, and the BDEI may perform intra-frame deinterleaving.Details of inter-frame deinterleaving and intra-frame deinterleaving arethe same as the above description.

A BICM decoding block illustrated in FIGS. 39 and 40 may perform areverse operation of the BICM chain block of FIGS. 37 and 38.

FIG. 40 is a block diagram including a second example of the structureof the hybrid time deinterleaver.

The hybrid time deinterleaver according to the second example mayperform an operation corresponding to a reverse operation of the hybridtime interleaver according to the second example described above. Anoperation of each block included in the second example of the structureof the hybrid time deinterleaver may be the same as the abovedescription in FIG. 39.

It is possible to determine whether to apply a BDI according to thesecond example of the structure of the hybrid time deinterleaverdepending on values of PLP_NUM. Each block of the hybrid timedeinterleaver according to the second example may perform operationsaccording to embodiments of the present invention. In this instance, anapplied structure and operation of a CDI may be different between a caseof PLP_NUM=1 and a case of PLP_NUM>1.

FIG. 41 is a diagram illustrating a protocol stack for supporting ahybrid-based next-generation broadcast service according to anembodiment of the present invention.

In a broadcast transmitter, a data link (encapsulation) layer deliversan MPEG-2 TS and/or IP packet, which is delivered from an upper layer,to a physical layer. Further, signalling information necessary for anoperation of the physical layer may be delivered.

The data link layer may be referred to by various terms such asencapsulation layer, link layer, Layer 2, etc.

A broadcast system according to the present invention may correspond toa hybrid broadcast system in which an IP centric broadcast network iscombined with broadband. In addition, the broadcast system according tothe present invention may be designed to be compatible with an existingMPEG-2 based broadcast system.

The broadcast system according to the present invention may correspondto a hybrid broadcast system based on a combination of an IP centricbroadcast network, a broadband network, and/or a mobile communicationnetwork (or cellular network).

Further, the physical layer may use a physical protocol employed in abroadcast system such as an ATSC system and/or a DVB system.

In a broadcast receiver, a link layer acquires an IP datagram frominformation which is acquired from a physical layer, or converts theacquired IP datagram into a particular frame (for example, RS frame,GSE-lite, GSE, or signal frame). Here, a frame may include a set of IPdatagrams.

A broadcast service according to an embodiment of the present inventionmay provide an additional service such as an HTML5 application, aninteractive service, an ACR service, a second screen service, apersonalization service, etc. in addition to audio/video (A/V) data.Further, an emergency alert service may be provided as the broadcastservice.

The broadcast service may be received by the broadcast receiver througha broadcast network such as a terrestrial broadcast network, a cablesatellite, etc., that is, a physical layer. In addition, the broadcastservice according to the present embodiment may be received through abroadband network.

MPEG2 TS encapsulation may acquire an MPEG2 TS using informationacquired from the physical layer. An FIC corresponds to signalinginformation, which is also referred to as an FIT or an SLT, and mayinclude information necessary to acquire a service and/or content,and/or information necessary to scan a channel.

The broadcast receiver may extract a UDP datagram from the acquired IPdatagram, and extract signaling information from the extracted UDPdatagram. In this instance, the signaling information may have an XMLform. In addition, the broadcast receiver may extract an asynchronouslayered coding/layered coding transport (ALC/LCT) packet from theextracted UDP datagram. Further, the broadcast receiver may extract afile delivery over unidirectional transport (FLUTE) packet from theALC/LCT packet. In this instance, the FLUTE packet may include real-timeaudio/video/captioning data, NRT data, and ESG data. Furthermore, thebroadcast receiver may extract a real-time transport protocol (RTP)packet and an RTP control protocol (RTCP) packet from the extracted UDPdatagram. In addition, the broadcast receiver may extract A/V data andadditional data from a real-time transport packet such as the extractedRTP/RTCP packet. In this instance, at least one of the NRT data, the A/Vdata, and the additional data may have the form of an ISO base mediafile format (ISO BMFF). In addition, the broadcast receiver may extractsignaling information such as NRT data, A/V data, and PSI/PSIP from theMPEG-2 TS packet or the IP packet. In this instance, the signalinginformation may have the XML or binary form, and may include informationfor supporting effective acquisition of a service and/or content.

Meanwhile, when the broadcast service is transmitted through thebroadband network, the broadcast receiver may receive an IP packet fromthe broadband network. The broadcast receiver may extract a TCP packetfrom the IP packet. Further, the broadcast receiver may extract an HTTPpacket from the extracted TCP packet, and extract A/V data, additionaldata, signaling information, etc. from the extracted HTTP packet. Inthis instance, at least one of the A/V data and the additional data mayhave an ISO BMFF form. In addition, the signaling information may havean XML form.

The broadcast receiver may combine data received through theabove-described protocol stack to provide a viewer with various enhancedservices such as an interactive service, a second screen service, anemergency alert service, etc.

FIG. 42 illustrates another example of the protocol stack for supportingthe broadcast service according to the present invention.

In FIG. 42, the broadcast service may be provided in an applicationform. In FIG. 42, the broadcast service may be transmitted through abroadcast network such as a terrestrial broadcast network, a cablesatellite, etc., that is, a physical layer, and may be transmittedthrough a broadband network.

When the broadcast service is received through the physical layer of thebroadcast network, the broadcast receiver may acquire an IP datagramusing information acquired from the physical layer. In addition, thebroadcast receiver may extract a UDP datagram from the acquired IPdatagram, and extract at least one of MMTP sessions, ROUTE sessions, andsignaling information (for example, FIT, MMT specific signaling, andROUTE specific signaling) from the extracted UDP datagram. Further, thebroadcast receiver provides the broadcast service by decoding MPUsreceived through the MMTP sessions based on the extracted signalinginformation or by decoding MPEG-DASH segments received through the ROUTEsession.

Meanwhile, when the broadcast service is transmitted through thebroadband network, the broadcast receiver may receive an IP packet fromthe broadband network. The broadcast receiver may extract a TCP packetfrom the IP packet. In addition, the broadcast receiver may extract anHTTP packet from the extracted TCP packet, and provide the broadcastservice by decoding an MPEG-DASH segment transmitted through theextracted HTTP packet or provide an NRT service by processing NRT files.In other words, in the case of the broadband network, data encapsulatedin the ISO BMFF form may be delivered to a receiving side based on astreaming scheme. For example, the streaming scheme may includeMPEG-DASH.

In this instance, video data, audio data, captioning data, etc. in datafor the broadcast service may be encapsulated in the ISO BMFF form. Forexample, the data encapsulated in the ISO BMFF form may conform to aform such as a segment of MPEG-DASH or an MPU of MMTP.

Here, ROUTE is a protocol for transmission of files through IP multicastnetworks. The ROUTE protocol uses ALC and LCT corresponding to baseprotocols designed for massively scalable multicast distribution, andother well-known Internet standards. ROUTE is an improved version orfunctional substitute having additional characteristics when compared toFLUTE. ROUTE may transmit signaling messages, ESG messages, and NRTcontent. In particular, ROUTE is suitable for transmission of streamingmedia such as MPEG-DASH media segment files. When compared to FLUTE,ROUTE provides lower end-to-end latency through a delivery chain. Inaddition, ROUTE provides an easy MPEG-DASH combination. The MPEG-DASHcombination allows synergy between broadcast and broadband deliverymodes.

One ROUTE session may include at least one LCT transport session. LCTtransport sessions may be a subset of the ROUTE session. For mediadelivery, one LCT transport session may typically transmit one mediacomponent (for example, DASH representation). From the viewpoint ofbroadcast DASH, the ROUTE session may be regarded as a complex of theLCT transport session transmitting at least one media componentcorresponding to a component of at least one DASH media representation.At least one relevant object may be transmitted in each LCT transportsession. For example, objects may be DASH segments related to onerepresentation. Together with each object, metadata properties may bedelivered such that the objects can be used in applications. Theapplications may include DASH media presentations, HTML-5 presentations,or other object-consuming applications, and are not restricted thereto.The ROUTE sessions may or may not be bounded in a temporal sense (TheROUTE sessions may be bounded or unbounded from the temporalperspective). The ROUTE session may include at least one LCT transportsession. Each transport session is uniquely identified by a unique TSIpresent in an LCT header.

In addition, a representation of MPEG-DASH has a concept correspondingto an MMTP packet flow in the MMT protocol, and may be mapped to anasset identifier (or asset ID, asset_id). Further, a segment ofMPEG-DASH has a concept corresponding to an MPU in the MMT protocol, andmay be mapped to information (or an MPU identifier) included in an mmpubox.

Signaling data (also referred to as signaling information) such as anFIT, MMT specific signaling, ROUTE specific signaling, etc. may betransmitted using a scheme below.

In the case of a broadcast network, the signaling data may betransmitted through a particular physical layer pipe, etc. correspondingto a particular data pipe of a physical layer frame (or frame) deliveredto a physical layer of the broadcast network and a next-generationbroadcast transmission system according to attributes of signaling. Forexample, signaling may be encapsulated in a bit stream or IP/UDPdatagram. In the case of a broadband network, signaling data may bereturned and delivered in response to a request from a receiver.

The FIT corresponds to low level signaling, and may be referred to as anFIC or an SLT. The broadcast receiver builds a basic service list basedon the FIT, and allows bootstrapping of discovery of service layersignaling for each service. The FIT (or SLT) may be transmitted throughlink layer signaling. Alternatively, the FIT (or SLT) may be transmittedin each physical layer frame for rapid acquisition. According to a givenembodiment, the FIT (or SLT) may be transmitted through at least one ofa physical layer pipe that transmits a physical layer frame and a signaland/or a physical layer pipe that transmits data to be actuallyserviced. Hereinafter, a description will be focused on the FIT.

SLS such as MMT specific signaling or ROUTE specific signaling enablesthe receiver to discover and access at least one service and/or at leastone content component. When the SLS is transmitted through the broadcastnetwork, the SLS may be transmitted in at least one LCT session includedin a ROUTE session by ROUTE/UDP/IP. In this instance, the SLS may betransmitted at a suitable carousel rate that supports rapid channeljoining and switching. When the SLS is transmitted through the broadbandnetwork, the SLS may be transmitted by HTTP(S)/TCP/IP.

ESG data and NRT content data may be transmitted using a scheme below.

In the case of the broadcast network, the ESG data and NRT content datamay be encapsulated in an application layer transport protocol packet.Then, the data encapsulated in the application layer transport protocolpacket may be similarly transmitted as described above.

In the case of the broadband network, the ESG data and NRT content datamay be returned and delivered in response to a request from thereceiver.

A relation between a ROUTE/LCT session and/or an MMTP session fortransmitting at least one content component of a service is as below.

For broadcast delivery of a linear service without app-basedenhancement, a content component of the service may be transmittedthrough 1) at least one ROUTE/LCT session and/or 2) at least one MMTPsession.

For broadcast delivery of a linear service with app-based enhancement, acontent component of the service may be transmitted only through 1) atleast one ROUTE/LCT session. Alternatively, the content component of theservice may be transmitted through at least one ROUTE/LCT session and/orat least one MMPT session.

For broadcast delivery of an app-based service, a content component ofthe service may be transmitted through at least one ROUTE/LCT session.

Each ROUTE session may include at least one LCT session. Each LCTsession may include all or some content components included in theservice.

In transmission of streaming services, the LCT session may transmit aseparate component of a user service such as an audio, video, and/orclosed caption stream. Streaming media may be formatted in at least oneDASH segment by MPEG-DASH.

Each MMTP session may include at least one MMTP packet flow. Each MMTPpacket flow may transmit an MMT signaling message. In addition, eachMMTP packet flow may include some or all content components included inthe service.

The MMTP packet flow may transmit at least one content componentformatted in at least one MPU by an MMT signaling message and/or an MMT.

For transmission of an NRT user service and/or system metadata, the LCTsession may transmit at least one file-based content item. The at leastone file-based content item may include a time-based or non-time-basedmedia component of the NRT service. In addition, the at least onefile-based content item may include service signaling and/or an ESGfragment.

A broadcast stream may be an abstract concept of an RF channel. The RFchannel may be defined based on a carrier frequency within a particularbandwidth. The RF channel may be defined by a pair of [geographic area,frequency]. Information about the geographic area and the frequency maybe defined and/or maintained by administrative authorities together witha BSID. A PLP (or DP) may correspond to a portion of the RF channel.

Each PLP (or DP) may include at least one modulation and/or codingparameter. The PLP (or DP) may be identified by a PLP (or DP) identifier(PLPID or DPID) having a unique value within a broadcast stream to whichthe PLP (or DP) belongs.

Each service may be identified by two types of service IDs. One typecorresponds to a compressed form, which is used in an FIT and has aunique value only within a broadcast area. The other type corresponds toa globally unique form used in SLS and/or ESG.

A ROUTE session may be identified by a source IP address, a destinationIP address, and/or a destination port number. An LCT session may beidentified by a unique TSI within a parent ROUTE session.

An S-TSID may include information about common characteristics of atleast one LCT session and/or a unique characteristic of at least oneindividual LCT session. The S-TSID may be a ROUTE signaling structure,and may be a part of service level signaling.

Each LCT session may be transmitted through one PLP (or DP). DifferentLCT sessions within one ROUTE session may be included in different PLPs(DPs) or the same PLP (or DP).

At least one characteristic described in the S-TSID may include a TSIand a PLPID (or DPID) for each LCT session, at least one descriptor forat least one delivery object or file, and/or at least one applicationlayer FEC parameter.

An MMT session may be identified by a source IP address, a destinationIP address, and/or a destination port number. An MMTP packet flow may beidentified by a unique packet_id within a range of a parent MMTPsession.

An S-TSID may include information about a common characteristic of eachMMTP packet flow and/or a unique characteristic of at least oneindividual MMTP packet flow.

At least one characteristic of each MMTP session may be transmitted byan MMT signaling message which is transmitted within the MMTP session.

Each MMTP packet flow may be transmitted through one PLP (or DP).Different MMTP packet flows within one MMTP session may be included indifferent PLPs (DPs) or included in the same PLP (or DP).

At least one characteristic described in an MMT signaling message mayinclude a packet_id and/or a PLPID (or DPID) of each MMTP packet flow.

FIG. 43 illustrates a configuration of a media contenttransmission/reception system through an IP network, that is, abroadband network according to an embodiment of the invention.

Transmission/reception of media content according to an embodiment ofthe present invention is divided into transmission/reception of atransmission packet including actual media content andtransmission/reception of media content reproduction information. Abroadcast receiver 55 receives the media content reproductioninformation, and receives the transmission packet including the mediacontent. In this instance, the media content reproduction informationindicates information necessary to reproduce media content. The mediacontent reproduction information may include at least one of spatialinformation and temporal information necessary to reproduce mediacontent. The broadcast receiver 55 reproduces media content based on themedia content reproduction information.

For example, media content may be transmitted and received through an IPnetwork according to an MPEG-DASH standard. In this case, a contentserver 50 transmits MPD including the media content reproductioninformation. However, according to a specific embodiment, the MPD may betransmitted by an external server rather than the content server 50. Inaddition, the content server 50 transmits a segment including mediacontent based on a request from the broadcast receiver 55. The broadcastreceiver 55 receives the MPD. The broadcast receiver 55 requests thatthe content server transmit media content based on the MPD. Thebroadcast receiver 55 receives a transmission packet including mediacontent based on a request. The broadcast receiver 55 reproduces themedia content based on the MPD. To this end, the broadcast receiver 55may include a DASH client. The DASH client may include an MPD parserthat parses the MPD, a segment parser that parses a segment, an HTTPclient that transmits an HTTP request message and receives an HTTPresponse message through an IP transceiver (not illustrated), and amedia engine that reproduces media.

As another embodiment, media content may be transmitted and receivedthrough the IP network according to an MMT standard. In this instance,the content server 50 transmits a reproduction information document(presentation information document, PI document) including media contentreproduction information. In addition, the content server 50 transmitsan MMTP packet including media content based on a request from thebroadcast receiver 55. The broadcast receiver 55 receives the PIdocument. The broadcast receiver 55 receives a transmission packetincluding media content. The broadcast receiver 55 extracts mediacontent from the transmission packet including the media content. Thebroadcast receiver 55 reproduces the media content based on the PIdocument.

Meanwhile, the broadcast receiver may receive emergency informationrelated to a natural disaster, a terrorist attack, a war, etc. throughthe broadcast network. In addition, the broadcast receiver may reportthe information to a user. In this way, many people may rapidly andefficiently detect a national disaster situation. However, the user maynot detect an emergency alert unless the user continuously monitors thebroadcast receiver. Even when the user does not continuously monitor thebroadcast receiver, the user is likely to carry a linkage device such asa mobile phone, a tablet PC, etc. at all times. Therefore, when thebroadcast receiver can transmit an emergency alert to the linkagedevice, and the linkage device can display the emergency alert, thenational disaster situation may be rapidly and efficiently reported tothe user.

In the broadcast transmitter, an emergency alert message may begenerated in the form of a section table or a packet in a link layer,and then transmitted to a physical layer. Alternatively, the emergencyalert message may be directly input to the physical layer withoutpassing through the link layer. In the physical layer, the emergencyalert message may be assigned to a physical layer pipe symbol, i.e. adata pipe symbol within the frame, and transmitted. Here, a physicallayer pipe may be a data pipe that transmits signaling information, adata pipe that transmits actual data, or a general data pipe, use ofwhich is not designated. Alternatively, as described in the foregoing,in the physical layer, the emergency alert message may be assigned tobetween a PLS symbol and a data pipe symbol within the frame, andtransmitted. In addition, emergency alert-related signaling informationmay be transmitted through a physical layer parameter symbol within theframe, or may be included in a transmission parameter of the physicallayer as described above and transmitted through a preamble symbol or aPLS symbol. The emergency alert-related signaling informationtransmitted through the preamble symbol or the PLS symbol may besignaled to at least one of an EAC_FLAG field, anEAS_WAKE_UP_VERSION_NUM field, an EAC_LENGTH_BYTE field, an EAC_COUNTERfield, and an EA_WAKE_UP field. In this instance, it is possible torefer to or not refer to information provided in the link layer or theupper layer. Details of each field have been described above, and areomitted here.

Next, a description will be given of examples of transmitting andreceiving an emergency alert message by the broadcast transmitter andthe broadcast receiver according to the invention. In particular,signaling information for receiving and decoding an emergency alertmessage is needed when the broadcast receiver receives the emergencyalert message and provides an emergency alert service to the user, andthe present invention describes a method of signaling the emergencyalert message.

FIG. 44 is a block diagram of an emergency alert system according to anembodiment of the present invention, and the emergency alert systemincludes a broadcast transmitter 72 for transmitting an emergency alertmessage, and a broadcast receiver 70 for receiving and processing theemergency alert message transmitted from the broadcast transmitter 72.In addition, the emergency alert system may further include alertauthorities 76 and an information aggregator 74.

In this instance, the emergency alert message refers to a messageobtained by converting emergency alert information for reporting anemergency state to a broadcast viewer in a form which is transmissiblethrough the broadcast network. Delivery of emergency alert, normallyemergency alert information, is normally led and operated by agovernment, and thus a specific structure may vary according to nationto which a broadcast system is applied. Therefore, in the presentembodiment, a description will be given of a method of configuring anemergency alert message and a method and apparatus fortransmitting/receiving the emergency alert message which are commonlyapplicable to a method of transmitting emergency alert informationthrough the broadcast network.

The alert authorities 76 may include a nation or an institution of acorresponding region. When transmission of emergency alert informationneeds to be delivered through the broadcast network, the alertauthorities 76 generate an emergency alert and deliver the emergencyalert to the information aggregator 74 (or institution). In thisinstance, the information aggregator 74 may be an integrated publicalert warning system (IPAWS) aggregator.

The information aggregator 74 configures the emergency alert informationto be delivered through the broadcast network as a common alertingprotocol (CAP)-based message, and delivers the information to thebroadcast transmitter 72. Here, the CAP corresponds to an XML fileformat for warning against an emergency state and exchanginginformation. The CAP may simultaneously propagate an emergency alertmessage through a plurality of emergency alert systems.

Hereinafter, a description will be focused on a process after the CAPmessage is delivered to the broadcast transmitter 72.

In response to the CAP message delivered to the broadcast transmitter72, the broadcast transmitter 72, which processes the message, transmitsrelated A/V content and an additional service together with the CAPmessage. Specifically, the broadcast transmitter 72 inserts the relatedA/V content or the additional service together with the CAP message intoa broadcast signal, and transmits the broadcast signal to the broadcastreceiver 70. According to a given embodiment, emergency alert-relateddata including the CAP message may be transmitted through differentroutes according to purpose and form. As a specific example, a differentroute may correspond to one of a signaling channel, a physical layerpipe, and a broadband network.

The broadcast receiver 70 receives the broadcast signal including theemergency alert-related data from the broadcast transmitter 72. Then,the broadcast receiver 70 decodes the broadcast signal received throughan emergency alert signaling decoder. The broadcast receiver 70 receivesan A/V service according to information acquired by decoding thebroadcast signal. Specifically, the broadcast receiver 70 may acquirephysical layer frame information including the A/V service from thebroadcast signal. In this instance, a physical layer frame maycorrespond to a unit of data transmitted through a physical layer pipe.In addition, the broadcast receiver 70 may receive A/V service datarelated to an emergency alert message from the physical layer frame.

Further, the broadcast receiver 70 may extract NRT service informationrelated to an emergency alert from the information acquired by decodingthe broadcast signal. Specifically, the NRT service information may beaddress information that allows an NRT service to be acquired. Forexample, the NRT service may be delivered via broadband, and the addressinformation may be URI information for acquiring the NRT service.

According to an embodiment of the present invention, the broadcasttransmitter 72 may transmit an emergency alert message through aprotocol layer included in a protocol stack. In this case, the protocollayer may be a link layer. According to an embodiment, the broadcasttransmitter 72 may format the emergency alert message in the form of atable according to a transport protocol. In this instance, the emergencyalert message may be formatted in the form of a table in the link layerincluded in the protocol stack. In addition, the emergency alert messagemay include information that signals link layer and physical layeroperations.

According to another embodiment, the broadcast transmitter 72 maypacketize the emergency alert message according to the transportprotocol. Specifically, the broadcast transmitter 72 may encapsulate theemergency alert message in the physical layer frame. In this case,emergency alert information may be prevented from being signaled to thebroadcast receiver 70 through several layers.

For transmission, the emergency alert message needs to be configured ina form that can be transmitted in the broadcast system. To this end, inan embodiment, a table in the form of a section may be generally used totransmit the emergency alert message. In another embodiment, theemergency alert message may be transmitted as a part of another sectiontable in a configuration of a descriptor form. In still anotherembodiment, the emergency alert message may be transmitted in a packetof a physical layer. Specifically, the emergency alert message may betransmitted in the form of a packet through a data pipe corresponding toa physical layer pipe. In this case, the emergency alert message may beincluded in a payload, which is included in a packet, and transmitted.

FIG. 45 illustrates syntax of EAT information according to an embodimentof the present invention. In this instance, an EAT may have a form of anemergency alert message. In an embodiment, when the emergency alertmessage (also referred to as an EAS message) is transmitted in a payloadof a packet, EAT information corresponding to signaling information ofthe emergency alert message may be included in a header of the packet.In another embodiment, the EAT information may be included in anextended header.

As illustrated in FIG. 45, the EAT information may include versioninformation of a protocol included in an EAT. In a specific example, theinformation may be an EAT_protocol_version field.

In addition, the EAT information may include information that reportswhether to automatically tune to a channel to the broadcast receiver 70.For example, the EAT information may include information that reportswhether to automatically tune to a channel on which specific informationabout an emergency alert is reported to the broadcast receiver 70. In aspecific example, the information that reports whether to automaticallytune to a channel may be an automatic_tuning_flag field.

In addition, the EAT information may include information about thenumber of messages included in the EAT. In a specific example, theinformation about the number of messages may be a num_EAS_message field.

FIG. 46 illustrates syntax of an emergency alert message according to anembodiment of the present invention. In an embodiment of the presentinvention, the emergency alert message may directly include a CAPmessage. In another embodiment, the emergency alert message may includeinformation about a route through which the CAP message is delivered. Inaddition, the emergency alert message may be included in an EAT andtransmitted.

As illustrated in FIG. 46, the emergency alert message according to thepresent embodiment may include identifier information for identifying anEAS message. In a specific embodiment, the identifier information may bean EAS_message_id field. In this case, the EAS_message_id field maycorrespond to 32 bits.

In addition, syntax for the emergency alert message may includeinformation that indicates an IP version. In this case, the versioninformation may be an EAS_IP_version_flag field. In a specificembodiment, when the EAS_IP_version_flag field has a value of 0, thevalue may indicate that an IP version is IPv4. In another embodiment,when the EAS_IP_version_flag field has a value of 1, the value mayindicate that an IP version is IPv6. The EAS_IP_version_flag field maycorrespond to 1 bit.

Further, the emergency alert message may include information thatindicates a delivery form of the EAS message. In this case, theinformation that indicates a delivery form of the EAS message may be anEAS_message_transfer_type field. The EAS_message_transfer_type field maycorrespond to 3 bits.

In a specific embodiment, the EAS_message_transfer_type field mayindicate that a delivery form of the emergency alert message, that is,the EAS message, has not been specified. In this case, theEAS_message_transfer_type field may have a value of 000(2).

In another embodiment, the EAS_message_transfer_type field may indicatethat a delivery form of the EAS message is a form not including theemergency alert message. In other words, the field may indicate that theEAT transmitted through a broadcast signal only includes informationabout A/V content without the emergency alert message. In this case, theEAS_message_transfer_type field may have a value of 001(2).

In another embodiment, the EAS_message_transfer_type field may indicatethat the EAS message is included in the EAT and delivered. In this case,the EAS_message_transfer_type field may have a value of 010(2).

Further, when the EAS_message_transfer_type field has the value of010(2), a table including the EAS message may indicate a length of theEAS message. In this case, information indicating the length of the EASmessage may be an EAS_message_length field. The EAS_message_length fieldmay correspond to 12 bits. In addition, when theEAS_message_transfer_type field has the value of 010(2), the tableincluding the EAS message may additionally include information about theEAS message.

In another embodiment, the EAS_message_transfer_type field may indicatethat the EAS message is transmitted through a data pipe corresponding toa physical layer pipe in the form of an IP datagram. In this case, theEAS_message_transfer_type field may have a value of 011(2). Further,when the EAS_message_transfer_type field has the value of 011(2), thetable including the emergency alert message may additionally include oneof IP address information for acquiring an IP datagram, UDP portinformation, and information about a transmitted physical layer frame.

In addition, the emergency alert message may include information thatindicates an encoding type of the EAS message. In this case, theinformation about the encoding type of the EAS message may be anEAS_message_encoding_type field. The EAS_message_encoding_type field maycorrespond to 3 bits.

In a specific embodiment, the EAS_message_encoding_type field mayindicate that the encoding type of the EAS message has not beenspecified. In this case, the EAS_message_encoding_type field may have avalue of 000(2).

In another embodiment, the EAS_message_encoding_type field may indicatethat the EAS message has not be encoded. In this case, theEAS_message_encoding_type field may have a value of 001(2).

In another embodiment, the EAS_message_encoding_type field may indicatethat the EAS message has been encoded by a DEFLATE algorithm. TheDEFLATE algorithm is a lossless compression data format. In this case,the EAS_message_encoding_type field may have a value of 010(2).

In addition, the emergency alert message may indicate whetherinformation about NRT content and additional data related to thereceived EAS message is included in the emergency alert table. In thiscase, information indicating whether the NRT content and the additionaldata are present may be an EAS_NRT_flag field. The EAS_NRT_flag fieldmay correspond to 1 bit.

In a specific embodiment, when the EAS_NRT_flag field is set to 0, thefield indicates that the information about the NRT content related tothe received EAS message is not included in the emergency alert table.In another embodiment, when the EAS_NRT_flag field is set to 1, thefield indicates that the information about the NRT content related tothe received EAS message is included in the table.

FIG. 47 illustrates syntax for automatic channel tuning informationaccording to an embodiment of the present invention. When A/V contentrelated to an emergency alert is transmitted simultaneously with theemergency alert message, the automatic channel tuning informationincludes information for automatically tuning to a channel on which theA/V content related to the emergency alert is transmitted. In otherwords, when a channel currently displayed in the broadcast receiver 70does not include content that includes the emergency alert message, theautomatic channel tuning information is information for automaticallytuning to the channel on which the A/V content related to the emergencyalert is transmitted. In a specific embodiment, the emergency alerttable may include the automatic channel tuning information when theautomatic_tuning_flag field of FIG. 45 is enabled. For example, when theautomatic_tuning_flag field has a value of 1, the emergency alert tablemay include the automatic channel tuning information.

In an embodiment, a table for the automatic channel tuning informationmay indicate information about a number of a channel to be tuned to.Specifically, the table may indicate information about a channelincluding content related to the emergency alert information. In thiscase, the information about the number of the channel to be tuned to maybe an automatic_tuning_channel_number field. In a specific embodiment,the automatic_tuning_channel_number field may correspond to 8 bits.

In another embodiment, the table for the automatic channel tuninginformation may indicate route information for receiving content relatedto the emergency alert message. Specifically, the table for theautomatic channel tuning information may indicate information foridentifying a physical layer frame including the A/V content related tothe emergency alert message. In this case, the information may be anautomatic_tuning_DP_id field. The automatic_tuning_DP_id field maycorrespond to 8 bits.

In another embodiment, the table for the automatic channel tuninginformation may indicate identification information of content relatedto the emergency alert message. Specifically, the table may indicateservice ID information of content related to the emergency alertmessage. In this case, the information may be anautomatic_tuning_service_id field. The automatic_tuning_service_id fieldmay correspond to 16 bits.

FIG. 48 illustrates syntax for NRT service information related to anemergency alert message according to an embodiment of the presentinvention. In other words, the NRT service information includesinformation for acquiring NRT data related to the emergency alertmessage. The NRT service information may be included in an EAT when theEAS_NRT_flag field of FIG. 46 is enabled. For example, the NRT serviceinformation may be included in the EAT when the EAS_NRT_flag field has avalue of 1.

When NRT content and data related to the emergency alert message aretransmitted to the broadcast receiver 70, the NRT service informationincludes identifier information for an NRT service. In this instance,the identifier information for the NRT service may be anEAS_NRT_service_id field. The EAS_NRT_service_id field may correspond to16 bits.

FIG. 49 illustrates an embodiment of an EAT having a section form fortransmitting an emergency alert message according to an embodiment ofthe present invention. Even though the EAT of FIG. 49 is prepared in anMPEG-2 private section form to assist in understanding, a format of dataof the EAT is not restricted thereto.

Examples of fields transmissible through the EAT are given below.

A table_id field (8 bits) is a field for distinguishing a type of atable, and a table may be found to be the EAT through this field.

A section_syntax_indicator field (1 bit) is an indicator that defines asection form of the EAT. For example, the section form may be short-formsyntax (“0”) of MPEG.

A private_indicator field (1 bit) indicates whether the EAT conforms toa private section.

A section_length field (12 bits) indicates a section length of aremaining EAT after the field.

A table_id_extension field (16 bits) is dependent on a table, and is alogical part of a table_id field that provides a range of remainingfields. The table_id_extension field includes an EAT_rotocol_versionfield.

The EAT_protocol_version field (8 bits) reports a protocol version forpermitting an EAT transmitted by a parameter having a differentstructure from that of others defined in a current protocol.

A version_number field (5 bits) indicates a version number of an EAT.

A current_next_indicator field (1 bit) indicates whether the EAT sectionis currently applicable.

A section_number field (8 bits) indicates a number of a current EATsection.

A last_section_number field (8 bits) indicates a last section numberincluded in an EAT.

An automatic_tuning_flag field (1 bit) indicates whether toautomatically tune to a channel.

A num_EAS_messages field (7 bit) indicates the number of emergency alertmessages included in an emergency alert table.

When the automatic_tuning_flag field has a value of “I”, that is,indicates automatic channel tuning, the emergency alert table furtherincludes an automatic_tuning_info( ) field. The automatic_tuning_info( )field includes information for automatic tuning. For example, theautomatic_tuning_info( ) field may include information about a channeltransmitting content related to emergency alert information, informationfor identifying a physical layer pipe transmitting A/V content relatedto an emergency alert message, and service ID information of contentrelated to the emergency alert message. Therefore, when forced tuning toa channel number at which the emergency alert message is broadcast isneeded, the above fields may be used.

In addition, an emergency_alert_message( ) field of FIG. 49 is includedin a “for” loop, and transmits an emergency alert message correspondingto a value of the num_EAS_messages field. When the EAS_NRT_flag fieldhas a value of 1, the “for” loop further includes an NRT_service_info( )field. The NRT_service_info( ) field transmits NRT service informationrelated to an emergency alert.

FIG. 50 illustrates another embodiment of a section table fortransmitting an emergency alert message according to the presentinvention.

In an emergency alert table of FIG. 50, a table_id field identifies atype of a current table. The broadcast receiver may identify the presenttable as an emergency alert table using the table_id field.

A table_id_extension field includes the EAT_protocol_version field. Whena structure of the emergency alert table is changed, theEAT_protocol_version field identifies version information thereof.Details of fields of a section header of FIG. 50 have been describedwith reference to FIG. 49, and will not be described here.

An automatic_tuning_flag field (1 bit) indicates whether toautomatically tune to a channel.

A num_EAS_messages field (7 bits) indicates the number of emergencyalert messages included in the emergency alert table.

When the automatic_tuning_flag field has a value of “1”, that is,indicates automatic channel tuning, the emergency alert table furtherincludes an automatic_tuning_channel_number field, an automatic_DP_idfield, and an automatic_service_id field.

The automatic_tuning_channel_number field (8 bits) indicates informationabout a channel including content related to emergency alertinformation.

The automatic_DP_id field (8 bits) indicates information for identifyinga data pipe, that is, a physical layer pipe including A/V contentrelated to the emergency alert message.

The automatic_service_id field (16 bits) indicates service IDinformation of content related to the emergency alert message.

In addition, a “for” loop repeated the number of times corresponding toa value of the num_EAS_messages field includes an EAS_message_id field,an EAS_IP_version_flag field, an EAS_message_transfer_type field, anEAS_message_encoding_type field, and an EAS_NRT_flag field.

The EAS_message_id field (32 bits) indicates a unique ID for identifyingan emergency alert message. A value of this field may be changed whenthe emergency alert message is updated or canceled. As anotherembodiment, this field may be extracted from a CAP message ID.

The EAS_IP_version_flag field (1 bit) indicates an IP version in whichthe emergency alert table is transmitted. The IP_address field includesan IPv4 address when this field has a value of “0” and includes an IPv6address when this field has a value of “1”.

The EAS_message_transfer_type field (3 bits) indicates a transmissiontype of the emergency alert message. In a specific embodiment, theEAS_message_transfer_type field may indicate that a transmission type ofan EAS message has not been specified. In this case, theEAS_message_transfer_type field may have a value of 000(2).

In another embodiment, the EAS_message_transfer_type field may indicatethat a transmission type of the EAS message is a type in which noemergency message is included. In this case, theEAS_message_transfer_type field may have a value of 001(2).

In another embodiment, the EAS_message_transfer_type field may indicatethat the EAS message is included in the EAT and delivered. In this case,the EAS_message_transfer_type field may have a value of 010(2).

Further, when the EAS_message_transfer_type field has the value of010(2), the emergency alert table including the EAS message mayadditionally indicate a length of the EAS message. In this case,information indicating the length of the EAS message may be anEAS_message_length field. The EAS_message_length field may correspond to12 bits. In addition, an EAS_message_bytes( ) field subsequent to theEAS_message_length field transmits an emergency alert message includingemergency alert content corresponding to a length which corresponds to avalue of the EAS_message_length field.

In another embodiment, the EAS_message_transfer_type field may indicatethat the EAS message is transmitted in the form of an IP datagramthrough a physical layer pipe. In this case, theEAS_message_transfer_type field may have a value of 011(2).

When the EAS_message_transfer_type field has the value of 011(2), theemergency alert table may additionally include at least one of anIP_address field (32 or 128 bits) indicating IP address information foracquiring an IP datagram that transmits the EAS message, a UDP_port_numfield (16 bits) indicating a UDP port number, and a DP_id field (8 bits)indicating identification information of a physical layer frame (thatis, a PLP or DP) in which the EAS message is transmitted.

Meanwhile, the EAS_message_encoding_type field (3 bits) indicates anencoding type of the emergency alert message. In a specific embodiment,the EAS_message_encoding_type field may indicate that an encoding typeof the emergency alert message has not been specified. In this case, theEAS_message_encoding_type field may have a value of 000(2).

In another embodiment, the EAS_message_encoding_type field may indicatethat the emergency alert message has not been encoded. In this case, theEAS_message_encoding_type field may have a value of 001(2).

In another embodiment, the EAS_message_encoding_type field may indicatethat the emergency alert message has been encoded by the DEFLATEalgorithm. The DEFLATE algorithm is a lossless compression data format.In this case, the EAS_message_encoding_type field may have a value of010(2).

In the emergency alert table, when the EAS_NRT_flag field has a value of“1”, an NRT_service_id field is further included. The NRT_service_idfield (16 bits) indicates identification information for identifying anNRT service related to an emergency alert.

FIG. 51 and FIG. 52 illustrate embodiments in which the EAT istransmitted in the form of a packet through a physical layer frameaccording to the invention.

In general, a broadcast packet includes a packet payload into which datato be transmitted through the packet is inserted, and a packet headerinto which information for signaling the packet payload is inserted.Therefore, according to an embodiment of the present invention, thebroadcast transmitter may insert an emergency alert message to betransmitted into the payload of the packet, and insert signalinginformation for signaling the emergency alert message into the header ofthe packet.

FIG. 51 illustrates an embodiment in which a form of the above-describedemergency alert table is not changed, and the emergency alert table isinserted into the payload of the packet without change and transmitted.As illustrated in FIG. 51, the packet payload includes the emergencyalert table without change, and may additionally include an ID for theemergency alert table and length information of the emergency alerttable.

In addition, the packet header may include information that indicates atype of the packet. In an embodiment, packet type information mayindicate that the payload of the packet includes data for emergencyalert signaling. In a specific embodiment, information indicating apacket type may be 110(2).

In addition, the packet header may include information that indicates atype of signaling data included in the payload of the packet. In anembodiment, signaling data type information may indicate that thesignaling data has the form of a section table. In a specificembodiment, when the signaling data type information has a value of00(2), the signaling data type information may indicate that thesignaling data has the form of a section table.

FIG. 52 illustrates an embodiment in which an emergency alert message isinserted into the packet payload as individual information rather thanin the form of a section table. In this instance, the section tablerefers to an intermediate form for configuring a final table.Specifically, the broadcast receiver 70 may configure the section tableby gathering packets, and the broadcast receiver 70 may configure thefinal table by gathering section tables. Therefore, the embodiment ofFIG. 52 illustrates that each field included in the emergency alertmessage is packetized into a separate packet. Thus, the broadcastreceiver 70 may acquire complete information from one packet without theneed to configure the section table by gathering one or more packets.For example, one packet payload may include only EAT protocol versioninformation, or include only automatic channel tuning information.

In this case, information that indicates a type of a packet may indicatethat a payload of the packet includes data for emergency alertsignaling. In this case, the information that indicates a type of apacket may be set to 110(2). In addition, information that indicates atype of signaling may indicate that data included in the packet payloadhas the form of individual information. In this case, the informationthat indicates a type of signaling may be set to 10(2).

Further, unlike FIG. 51, data for an emergency alert included in thepacket payload may vary, and thus the packet header may additionallyinclude information for identifying the data. The information may be anInfo Type field.

In a specific embodiment, when the Info Type field has a value of000(2), the data for an emergency alert included in the packet payloadmay be an emergency alert message. In another embodiment, when the InfoType field has a value of 001(2), the data for an emergency alertincluded in the packet payload may be automatic channel tuninginformation. In another embodiment, when the Info Type field has a valueof 010(2), the data for an emergency alert included in the packetpayload may be NRT service information.

Hereinafter, FIG. 53 to FIG. 59 illustrate various embodiments oftransmitting an EAT. In a specific embodiment, a PLP (or DP) thattransmits the EAT may vary according to embodiment, which will bedescribed through FIG. 53 to FIG. 59.

FIG. 53 is an embodiment of the present invention, and illustrates thatthe broadcast transmitter 72 transmits the EAT through a designated PLP(or DP).

In FIG. 53, reference numeral 70 denotes a broadcast receiver, referencenumeral 72 denotes a broadcast transmitter, and reference numeral 78denotes a physical layer processor included in each of the broadcasttransmitter 72 and the broadcast receiver 70. In an embodiment, when thephysical layer processor 78 is included in the broadcast transmitter, anemergency alert signaling formatting block for an emergency alertmessage and a delivery protocol block for A/V content correspond to alink layer processor. In addition, in an embodiment, when the physicallayer processor 78 is included in the broadcast receiver, an emergencyalert signaling decoding block and a parser block for the emergencyalert message and a protocol stack and a decoder block for the A/Vcontent correspond to the link layer processor.

In an embodiment, the broadcast transmitter 72 may transmit theemergency alert table through a designated physical layer pipe(dedicated physical layer pipe). In this instance, the physical layerpipe designated to transmit the emergency alert table may be referred toas an EAC. In other words, the EAC may be a dedicated physical layerpipe for transmitting only a physical layer frame including theemergency alert table. Here, the physical layer frame may be a unit ofdata transmitted through a physical layer. The physical layer mayinclude one or more physical layer pipes, and the physical layer framemay be transmitted through the physical layer pipes. Hereinafter, thepresent embodiment will be described in more detail with reference toFIG. 53.

The emergency alert signaling formatting block of the broadcasttransmitter 72 generates the EAT based on emergency alert informationgathered from the alert authorities 76, etc. Here, the emergency alertinformation gathered by the broadcast transmitter 72 may be a CAPmessage received from the information aggregator 74.

In addition, as described in the foregoing, the designated physicallayer pipe may be an emergency alert channel that transmits only theEAT. The physical layer processor 78 of the broadcast transmitter 72generates a broadcast signal including a generated emergency alerttable. Specifically, the broadcast signal may include a physical layerframe including the emergency alert table. In addition, the broadcasttransmitter 72 transmits the broadcast signal including the emergencyalert channel. Specifically, the broadcast transmitter 72 may transmitthe broadcast signal through a physical layer pipe designated only for aphysical layer frame including the EAT. The physical layer processor 78of the broadcast receiver 70 receives the broadcast signal through thedesignated physical layer pipe. As described in the foregoing, thephysical layer pipe may be a data pipe designated to transmit onlyemergency alert information in a physical layer. The decoding and parserblock of the broadcast receiver 70 may extract the EAT from the physicallayer frame received through the EAC. In addition, the broadcastreceiver 70 may acquire information, which indicates whether the EAC isincluded in the physical layer that delivers the physical layer frame,from the physical layer frame. In this instance, information indicatingwhether the EAC is included in the physical layer may be referred to asPHY signaling. The broadcast receiver 70 may determine a data pipe thattransmits emergency alert information based on the PHY signaling. Thedecoding block of the broadcast receiver 70 decodes a physical layerframe including the EAT. In this instance, the broadcast receiver 70 mayacquire a CAP message, related content information, and related NRTservice information from the physical layer frame.

The parser block of the broadcast receiver 70 may acquire the emergencyalert information by parsing the acquired CAP message. In a specificembodiment, the parser block (that is, CAP parser) may parse the CAPmessage. In this case, the broadcast receiver 70 may acquire the relatedNRT service information together with the emergency alert information.When overlapping information between the EAT and the CAP message ispresent, the broadcast transmitter 72 may adjust the information in aprocess of adjusting the EAT.

The protocol stack block of the broadcast receiver 70 may receive A/Vcontent based on the acquired related content information. Specifically,the acquired related content information may be information foridentifying a physical layer pipe that transmits the A/V content.Further, the related content information may be information foridentifying related A/V content.

The protocol stack block of the broadcast receiver 70 identifies aphysical layer pipe to extract a physical layer frame including therelated content based on the related content information. In addition,the decoder block of the broadcast receiver 70 decodes the physicallayer frame received through the identified physical layer pipe toacquire the A/V content. In this instance, the physical layer pipe thattransmits the related content may be distinguished from the physicallayer pipe that transmits the emergency alert information. In addition,the broadcast receiver 70 may acquire an NRT service related to theemergency alert information based on the acquired NRT serviceinformation. Specifically, the broadcast receiver 70 may acquire addressinformation for acquiring an NRT service from the NRT serviceinformation. In this instance, the broadcast receiver 70 may receive theNRT service through the broadband network.

The broadcast receiver 70 provides the acquired emergency alert messagetogether with the A/V content. When information about automatic channeltuning is transmitted, the broadcast receiver 70 may provide theemergency alert message while automatically tuning to a channelincluding the information about automatic channel tuning.

FIG. 54 and FIG. 55 illustrate that the broadcast transmitter 72encapsulates an EAT in a packet and transmits the packet as anembodiment of the present invention. The packet including the EAT may bereferred to as an emergency alert packet.

In an embodiment, a plurality of physical layer pipes may be included ina physical layer of a broadcast signal. In addition, a separate physicallayer pipe may be present to transmit specific information about aplurality of broadcast services transmitted through the plurality ofphysical layer pipes included in the physical layer of the broadcastsignal. In this instance, a separate physical layer pipe transmittingbroadcast service information may be referred to as a base data pipe.Specifically, the broadcast transmitter 72 may transmit signalinginformation of a broadcast service or common data applied to a pluralityof broadcast services through the base data pipe. Here, the signalinginformation or the common data may be information that signals aphysical layer frame transmitted through a physical layer or datacommonly applied to a physical layer frame.

FIG. 54 illustrates that the broadcast transmitter 72 transmits an EATthrough a base data pipe as an embodiment.

In FIG. 54, reference numeral 70 denotes a broadcast receiver, referencenumeral 72 denotes a broadcast transmitter, and reference numeral 78denotes a physical layer processor included in each of the broadcasttransmitter 72 and the broadcast receiver 70. In an embodiment, when thephysical layer processor 78 is included in the broadcast transmitter, anemergency alert packet encapsulation block for an emergency alertmessage and a delivery protocol block for A/V content correspond to alink layer processor. In addition, in an embodiment, when the physicallayer processor 78 is included in the broadcast receiver, afiltering/decoding block and a CAP parser block for the emergency alertmessage and a protocol stack and a decoder block for the A/V contentcorrespond to the link layer processor.

The emergency alert packet encapsulation block of the broadcasttransmitter 72 generates a packet to be transmitted through a physicallayer by encapsulating emergency alert information gathered from thealert authorities 76, etc. In this instance, a packet obtained byencapsulating the emergency alert information may be referred to as anemergency alert packet. Here, the emergency alert information receivedby the broadcast transmitter 72 may be a CAP message received from theinformation aggregator 74.

In an embodiment, the emergency alert packet may include a packet headerand a packet payload. In a specific embodiment, the packet payload mayinclude an EAT without change. In another embodiment, the packet payloadmay include only partial information in the EAT. Here, the partialinformation may be partial information having a high importance in theEAT.

In addition, the packet header may include signaling informationindicating that data included in the packet payload is emergency alertinformation. Further, the packet header may signal that the packetincludes the emergency alert information. Specifically, the packetheader may indicate that the packet includes different type informationfrom that of a general packet, and the packet includes emergency alertinformation. In other words, the packet header may indicate that thepacket is an emergency alert packet.

The physical layer processor 78 of the broadcast transmitter 72transmits a packet in which the EAT is encapsulated through a physicallayer pipe for transmitting signaling information of a broadcast serviceor common data. In other words, the broadcast transmitter 72 transmitsthe emergency alert packet through a base data pipe. In this case, thebase data pipe is a form of a physical layer pipe, and may bedistinguished from another physical layer pipe (or data pipe).

Meanwhile, a physical layer including the base data pipe may transmitinformation signaling that the base data pipe is present in the physicallayer. In this instance, the information signaling the presence of thebase data pipe may be referred to as PHY signaling. The physical layerprocessor 78 of the broadcast receiver 70 may verify that the base datapipe is present in a physical layer of a broadcast signal received basedon the PHY signaling. In addition, the physical layer processor 78 ofthe broadcast receiver 70 may acquire emergency alert informationthrough the base data pipe which is a form of the physical layer pipe.In this instance, the acquired emergency alert information may have theform of an emergency alert packet. The broadcast receiver 70 receives abroadcast signal through the base data pipe. In other words, thebroadcast receiver 70 receives a physical layer frame including theemergency alert packet through the base data pipe.

The filtering and decoding block of the broadcast receiver 70 mayextract the physical layer frame including the emergency alert packetfrom the received broadcast signal. In addition, the filtering anddecoding block of the broadcast receiver 70 may acquire the emergencyalert information by decoding the extracted physical layer frame.Specifically, the emergency alert information may be acquired bydecoding the emergency alert packet included in the physical layerframe.

In this instance, the emergency alert packet may include a packetpayload into which an EAT is inserted and a packet header that signalsthe packet payload. In a specific embodiment, the broadcast receiver 70may determine whether the packet includes the emergency alertinformation from the packet header. In other words, the broadcastreceiver 70 may determine whether the packet is an emergency alertpacket based on information extracted from the packet header.

In addition, the broadcast receiver 70 may determine a form of theemergency alert information included in the packet payload from thepacket header. For example, the broadcast receiver 70 may determinewhether the packet payload includes the whole EAT.

The broadcast receiver 70 acquires the emergency alert information fromthe packet payload based on the information acquired from the packetheader. Here, the acquired emergency alert information may be an EAT ora CAP message. Alternatively, the acquired emergency alert informationmay be emergency alert related content information or emergency alertrelated NRT service information.

The CAP parser block of the broadcast receiver 70 may parse the acquiredCAP message to acquire the emergency alert information. In this case,the broadcast receiver 70 may acquire related NRT service informationtogether with the emergency alert information. When overlappinginformation between the EAT and the CAP message is present, thebroadcast transmitter 72 may omit the overlapping information in aprocess of configuring the EAT. Hereinafter, a process of acquiring arelated service based on the emergency alert information is the same asthe above-described content, and thus is omitted.

FIG. 55 illustrates that the broadcast transmitter 72 transmits an EATthrough a normal physical layer pipe as an embodiment of the presentinvention. Here, the normal physical layer pipe may be a physical layerpipe, use of which is not designated.

The present embodiment is a case in which a base data pipe is notincluded in a physical layer unlike the embodiment of FIG. 54, and thedescription will focus on a difference from FIG. 54. That is, thephysical layer processor 78 is different between FIG. 55 and FIG. 54.

In the present embodiment, the emergency alert packet encapsulationblock of the broadcast transmitter 72 configures a packet headerdifferently from a general packet header while encapsulating emergencyalert information. Specifically, the broadcast transmitter 72 maydifferently set a value that indicates a packet type included in thepacket header. For example, the value may be set to 000(2) in a generalpacket and may be set to 110(2) in an emergency alert packet, therebydistinguishing between the packets.

Meanwhile, the physical layer processor 78 of the broadcast transmitter72 may transmit information that signals a physical layer pipe in aphysical layer. In this instance, the information that signals thephysical layer pipe in the physical layer may be referred to as PHYsignaling.

The physical layer processor 78 of the broadcast transmitter 72 mayacquire information of the physical layer pipe included in the physicallayer received based on the PHY signaling.

In the embodiment of FIG. 55, the broadcast receiver 70 may receive apacket including an emergency alert and a packet including broadcastcontent through a plurality of physical layer pipes included in thephysical layer. In addition, the broadcast receiver 70 may acquireemergency alert information from the packet including the emergencyalert. Further, the broadcast receiver 70 may identify another physicallayer pipe that transmits broadcast content related to the emergencyalert based on the emergency alert information. Furthermore, thebroadcast receiver 70 may acquire route information for receiving NRTcontent related to the emergency alert based on the emergency alertinformation.

FIG. 56 to FIG. 59 illustrate that the broadcast transmitter 72transmits emergency alert information through another form of thephysical layer pipe as an embodiment of the present invention. In thiscase, the other form of the physical layer pipe may be a physical layerpipe for scanning a broadcast service included in a physical layer of abroadcast signal. Specifically, the broadcast transmitter 72 maytransmit service signaling information for scanning a broadcast servicedirectly to the physical layer of the broadcast signal through aphysical layer pipe without passing through another layer. In thisinstance, the physical layer pipe for scanning the broadcast service maybe referred to as a signaling channel. The broadcast receiver 70 mayacquire at least one of configuration information of a broadcast stream,brief broadcast service information, and component information from thesignaling channel. In a specific embodiment, the signaling channel maybe one of an FIC and LLS. The FIC is also referred to as an FIT or anSLT.

In an embodiment of the present invention, the broadcast transmitter 72may transmit an emergency alert message based on a CAP message throughthe signaling channel. The present embodiment will be described in moredetail with reference to FIG. 56 and FIG. 57.

In FIG. 56, reference numeral 70 denotes a broadcast receiver, referencenumeral 72 denotes a broadcast transmitter, and reference numeral 78denotes a physical layer processor included in each of the broadcasttransmitter 72 and the broadcast receiver 70. In an embodiment, when thephysical layer processor 78 is included in the broadcast transmitter, anemergency alert signaling formatting block for an emergency alertmessage, an FIC signaling block for signaling channel information, and adelivery protocol block for A/V content correspond to a link layerprocessor. In addition, in an embodiment, when the physical layerprocessor 78 is included in the broadcast receiver, an emergency alertsignaling decoding block and a CAP parser block for the emergency alertmessage, an FIC decoding block for the signaling channel information,and a protocol stack and a decoder block for the A/V content correspondto the link layer processor.

In another embodiment of the present invention, the broadcasttransmitter 72 may transmit only minimum information that indicates anemergency alert through a signaling channel, and an actual emergencyalert message (for example, an EAT) may be transmitted through aphysical layer pipe distinguished from the signaling channel. Thepresent embodiment will be described in more detail with reference toFIG. 58 and FIG. 59. The physical layer processor 78 is differentbetween FIG. 58 and FIG. 56.

FIG. 56 illustrates a block diagram of an emergency alert system fordirectly transmitting an emergency alert message through a signalingchannel according to an embodiment of the present invention.

The emergency alert signaling formatting block of the broadcasttransmitter 72 generates an EAT based on emergency alert informationgathered from the alert authorities 76, etc. Here, the emergency alertinformation received by the broadcast transmitter 72 may be a CAPmessage received from the information aggregator 74.

The physical layer processor 78 of the broadcast transmitter 72generates a broadcast signal including the generated EAT. Specifically,the EAT may be transmitted through a signaling channel which is a formof a physical layer pipe of a broadcast signal. In this instance, thesignaling channel may refer to a general signaling channel rather than adesignated signaling channel described in the embodiment of FIG. 53. Inaddition, the broadcast transmitter 72 transmits a broadcast signalincluding the emergency alert information through the signaling channel.

The physical layer processor 78 of the broadcast receiver 70 may extracta physical layer frame including the emergency alert information fromthe broadcast signal received through the signaling channel.Specifically, the extracted physical layer frame may include the EAT.The decoding block of the broadcast receiver 70 decodes the extractedphysical layer frame. In a specific embodiment, the broadcast receiver70 decodes the physical layer frame to acquire the emergency alertinformation. In this instance, the broadcast receiver 70 may acquire aCAP message, emergency alert-related content information, and emergencyalert-related NRT service information from the physical layer frame.

The CAP parser block of the broadcast receiver 70 may parse the acquiredCAP message to acquire emergency alert information. In this case, thebroadcast receiver 70 may acquire the emergency alert-related NRTservice information together with the emergency alert information. Whenoverlapping information between the EAT and the CAP message is present,the broadcast transmitter 72 may omit the overlapping information in aprocess of configuring the EAT. Hereinafter, a process of acquiring arelated service based on the emergency alert information is the same asthe above-described content, and thus is omitted.

FIG. 57 illustrates syntax of the emergency alert message transmittedthrough the signaling channel according to the embodiment of FIG. 56. Ina specific embodiment, the emergency alert message may be a part of atable transmitted through the signaling channel. In addition, a fieldillustrated in FIG. 57 may be changed as necessary in the future.

FIG. 57 illustrates an example of transmitting the emergency alertmessage through an FIC in the signaling channel. In FIG. 57, aFIT_data_version field (8 bits) illustrates version information ofsemantics and syntax included in the FIC. A receiver according to anembodiment of the present invention may determine whether to processsignaling included in the FIC using the FIT_data_version field.

A num_broadcast field (8 bits) indicates the number of broadcasters thattransmit broadcast services or content through a frequency or atransmitted transmission frame.

An emergency_alert_flag field (1 bit) indicates whether emergencyalert-related signaling information is included in the FIC. In anembodiment, the emergency_alert_flag field indicates that the FIC doesnot include the emergency alert-related signaling information when theemergency_alert_flag field has a value of 0, and theemergency_alert_flag field indicates that the FIC includes the emergencyalert-related signaling information when the emergency_alert_flag fieldhas a value of 1.

The emergency alert-related signaling information may includeinformation related to automatic channel tuning. In addition, when theemergency_alert_flag field has the value of 1, an emergency alertmessage and/or emergency alert-related NRT service information may betransmitted through the FIC. To this end, when the emergency_alert_flagfield has the value of 1, the FIC includes an automatic_tuning_flagfield and a num_EAS_messages field. In addition, automatic channeltuning information, an emergency alert message, NRT service information,etc. may be transmitted through the FIC according to each field value.

The automatic_tuning_flag field (1 bit) indicates whether toautomatically tune to a channel.

The num_EAS_messages field (7 bits) indicates the number of emergencyalert messages included in the FIC.

When the automatic_tuning_flag field has a value of 1, that is,indicates automatic channel tuning, the FIC further includes anautomatic_tuning_info( ) field. The automatic_tuning_info( ) fieldincludes information for automatic tuning. For example, theautomatic_tuning_info( ) field may include at least one of informationabout a channel that transmits content related to emergency alertinformation, information for identifying a physical layer pipe thattransmits A/V content related to an emergency alert message, and serviceID information of content related to the emergency alert message.Therefore, when automatic channel tuning is needed, the above field maybe used.

In addition, an emergency_alert_message( ) field transmits an emergencyalert message, and an NRT_service_info( ) field transmits NRT serviceinformation related to an emergency alert while being repeated thenumber of times corresponding to a value of the num_EAS_messages field.

Meanwhile, in the FIC, a broadcast_id field (16 bits) indicates a uniqueID of a broadcaster that transmits content or a broadcast service or afrequency. In a broadcaster that transmits MPEG-2 TS-based data, abroadcast_id may have the same value as that of a transport_stream_id ofan MPEG-2 TS.

A delivery_system_id field (16 bits) indicates an ID of a broadcasttransmission system processed by applying the same transmissionparameter in a used broadcast network.

A base_DP_id field (8 bits) indicates an ID of a physical layer pipecorresponding to a data pipe that delivers a broadcast service signaltransmitted by a particular broadcaster which is identified by abroadcast_id. The base_DP_id field may indicate an ID of arepresentative data pipe, that is, a representative physical layer pipethat can decode a component included in a broadcast service transmittedby the particular broadcaster which is identified by the broadcast_id.Here, the physical layer pipe may refer to a data pipe of a physicallayer, and the broadcast service transmitted by the particularbroadcaster may include PSI/SI information, etc.

A base_DP_version field (5 bits) indicates version information accordingto change of data transmitted through a data pipe, that is, a PLPidentified by base_DP_id. For example, when a service signal such as aPSI/SI is delivered through a base DP, a value of the base_DP_versionfield may be incremented by 1 each time the service signal is changed.

A num_service field (8 bits) indicates the number of broadcast servicestransmitted by a broadcaster identified by a broadcast_id within acorresponding frequency or transport frame.

A service_id field (16 bits) indicates an ID that can identify acorresponding broadcast service.

A service_category field (8 bits) indicates a category of acorresponding broadcast service. For example, the service_category fieldmay indicate that the category is Basic TV when a value thereof is 0x01,the category is Basic Radio when a value thereof is 0x02, the categoryis RI service when a value thereof is 0x03, the category is ServiceGuide when a value thereof is 0x08, and the category is Emergency Alertwhen a value thereof is 0x09.

A service_hidden_flag field (1 bit) indicates whether a correspondingbroadcast service is hidden. When the service is hidden, the servicecorresponds to a test service or an internally used service, and thus areceiver according to an embodiment of the present invention may ignorethe above-described hidden broadcast service or hide the service from aservice list.

An SP_indicator field (1 bit) indicates whether service protection isapplied to one or more components in a corresponding broadcast service.

A num_component field (8 bits) indicates the number of componentsincluded in a corresponding broadcast service.

A component_id field (8 bits) indicates an ID that identifies acomponent in a broadcast service.

A DP_id field (16 bits) indicates an ID that identifies a PLPcorresponding to a data pipe through which a component in a broadcastservice is transmitted.

An RoHC_init_descriptor( ) transmits compression information in anembodiment such that the broadcast receiver may release compression of acomponent when the component is compressed in a broadcast service, inparticular, when a header of a packet that transmits the component iscompressed using an RoHC scheme.

FIG. 58 illustrates a block diagram of an emergency alert system fortransmitting/receiving only a delivery route of emergency alertinformation through a signaling channel according to an embodiment ofthe present invention. That is, an emergency alert message is nottransmitted through the signaling channel.

To this end, the broadcast transmitter 72 signals emergency alertinformation gathered from the alert authorities 76, etc. in atransmissible form.

Specifically, the broadcast transmitter 72 may configure signalinginformation for an emergency alert (for example, a CAP message andrelated data) in a table, a descriptor, or a packet. In this instance,when the broadcast transmitter 72 does not include a module only forseparate emergency alert signaling information, the emergency alertsignaling information (or emergency alert information) may be signaledthrough a general signaling module in a transmissible form.

The broadcast transmitter 72 may insert information about whether anemergency alert message is transmitted and information about a routethrough which the emergency alert message is transmitted together withthe emergency alert information into a physical layer frame. In thisinstance, the information about whether an emergency alert message istransmitted and the information about the transmission route may beindicated using an emergency alert indicator. The descriptor included inthe physical layer frame may include the emergency alert indicator. Inaddition, the table included in the physical layer frame may include theemergency alert indicator as a field. Information included in theemergency alert indicator may be included as a separate field asnecessary, and only information having high priority may be includedaccording to order of priority. Here, the order of priority may bedetermined for each piece of information according to importance intransmitting the emergency alert information.

A physical channel processor 78 of the broadcast transmitter 72transmits a physical layer frame including an emergency alert indicatorand related data. In addition, the physical channel processor 78 of thebroadcast transmitter 72 may transmit information related to anemergency alert through a physical layer pipe other than a signalingchannel. In this instance, the physical layer pipe other than thesignaling channel may be regarded as a general physical layer pipe.

In addition, emergency alert-related data transmitted by the broadcasttransmitter 72 may be path information for acquiring emergency alertinformation from a data pipe. Specifically, the emergency alert-relateddata may be information for identifying a general data pipecorresponding to a general physical layer pipe that transmits emergencyalert information.

A physical channel processor 78 of the broadcast receiver 70 receivesthe physical layer frame including the emergency alert indicator and therelated data through the signaling channel. In addition, the physicallayer frame may include information indicating whether a signalingchannel that transmits emergency alert information to a physical layeris present. In this instance, the information indicating whether thesignaling channel is present may be referred to as PHY signaling. Thebroadcast receiver 70 verifies whether the signaling channel is presentin the physical layer based on the PHY signaling, and receives thephysical layer frame including the emergency alert indicator and therelated data from the signaling channel.

The broadcast receiver 70 may decode the physical layer frame through anemergency alert signaling decoder, and acquire the emergency alertindicator and the related data from the physical layer frame.

The broadcast receiver 70 acquires delivery path information of theemergency alert message based on the emergency alert indicator and therelated data acquired from the physical layer frame. Specifically, thebroadcast receiver 70 may acquire information about the physical layerpipe through which the emergency alert message is transmitted from theemergency alert indicator. Specifically, the broadcast receiver 70 mayacquire identification information for identifying the physical layerpipe that transmits the emergency alert message from the emergency alertindicator.

The broadcast receiver 70 decodes a packet transmitted through thephysical layer pipe which is identified based on the emergency alertindicator.

In a specific embodiment, the broadcast receiver 70 may determinewhether the packet includes the emergency alert information based on apacket header. In addition, the broadcast receiver 70 may determine aform of the emergency alert information included in a packet payloadfrom the packet header. For example, the broadcast receiver 70 maydetermine whether the packet payload includes the whole EAT.

The broadcast receiver 70 acquires the emergency alert information fromthe packet payload based on information acquired from the packet header.Here, the acquired emergency alert information may be an EAT or a CAPmessage. Alternatively, the emergency alert information may be relatedcontent information or NRT service information.

The CAP parser block of the broadcast receiver 70 may acquire theemergency alert information by parsing the acquired CAP message. In thiscase, the broadcast receiver 70 may acquire related NRT serviceinformation together with the emergency alert information. Whenoverlapping information is present between the EAT and the CAP message,the overlapping part may be omitted in a process in which the broadcasttransmitter 72 configures the EAT.

The broadcast receiver 70 may receive A/V content based on the acquiredrelated content information. Specifically, the acquired related contentinformation may be information for identifying a data pipe thattransmits the A/V content. Further, the acquired related contentinformation may be information for identifying the A/V content. Thebroadcast receiver 70 identifies a data pipe that transmits the A/Vcontent based on the related content information. In addition, thebroadcast receiver 70 may acquire the A/V content by decoding a physicallayer frame transmitted through the identified data pipe, and acquirecontent related to the emergency alert information in the acquired A/Vcontent. In this instance, the physical layer pipe that transmits thecontent is distinguished from the physical layer pipe that transmits theemergency alert information. In addition, the broadcast receiver 70 mayacquire an NRT service related to the emergency alert information basedon the acquired NRT service information. Specifically, the broadcastreceiver 70 may acquire address information that allows the NRT serviceto be acquired from the NRT service information. In this instance, thebroadcast receiver 70 may receive the NRT service through the broadbandnetwork.

The broadcast receiver 70 may provide the acquired emergency alertmessage together with the A/V content. When information about automaticchannel tuning is transmitted together with the emergency alert message,the broadcast receiver 70 may provide the emergency alert message whileautomatically tuning to a channel.

FIG. 59 is an example of syntax for signaling an emergency alerttransmitted through a signaling channel according to the embodiment ofFIG. 58. In a specific embodiment, the emergency alert message may be apart of a table transmitted through the signaling channel. In addition,fields illustrated in FIG. 59 may be changed as necessary in the future.

FIG. 59 illustrates another example of transmitting emergency alertsignaling information which is transmitted through the FIC in thesignaling channel.

An FIC of FIG. 59 is the same as the FIC of FIG. 57 except that anEAS_message_id field and an EAS_DP_id field are added instead of theemergency_alert_message( ) field and the NRT_service_info( ) field ofFIG. 57. Therefore, fields not described with reference to FIG. 59 willbe inferred from FIG. 57, and a description thereof will be omittedherein.

The EAS_message_id field (32 bits) of FIG. 59 indicates an ID foridentifying an emergency alert message transmitted through a data pipewhich is identified by the EAS_DP_id field.

In addition, the EAS_DP_id field (8 bits) indicates an ID foridentifying a data pipe (that is, a PLP) that transmits an emergencyalert message which is identified by the EAS_message_id field.

Meanwhile, the EAS_message_id field and the EAS_DP_id field of the FICof FIG. 59 may be used as an emergency alert indicator that indicateswhether the emergency alert message is transmitted and information abouta transmission path.

FIG. 60 is a flowchart illustrating an operation method of the broadcasttransmitter 72 according to an embodiment of the present invention.

The broadcast transmitter 72 receives emergency alert information fromthe alert authorities 76 (S101). Here, the alert authorities 76 may beone of disaster management authorities and an involved department. Inaddition, the broadcast transmitter 72 may receive the emergency alertinformation from the information aggregator 74. In this case, thebroadcast transmitter 72 may receive the emergency alert informationprocessed in a CAP message.

The broadcast transmitter 72 generates a table including the emergencyalert information or an emergency alert packet including the emergencyalert information based on the received emergency alert information(S103). Specifically, the broadcast transmitter 72 may generate an EATor an emergency alert packet according to a physical layer pipe thattransmits the emergency alert information.

In an embodiment, when the emergency alert information is transmittedthrough a designated physical layer pipe, the broadcast transmitter 72may generate an EAT including the emergency alert information. In thiscase, in a first embodiment, the EAT may include all of the emergencyalert information. In addition, in a second embodiment, the EAT mayinclude some of the emergency alert information. Here, the some of theemergency alert information may include minimum information fortransmitting the whole emergency alert information.

In another embodiment, when the broadcast transmitter 72 transmits theemergency alert information through a physical layer pipe for packettransmission, the broadcast transmitter 72 may encapsulate the emergencyalert information in a packet. The packet in which the emergency alertinformation is encapsulated may be referred to as an emergency alertpacket. In an embodiment, the broadcast transmitter 72 may encapsulatethe emergency alert information in a payload of the packet. In anotherembodiment, the broadcast transmitter 72 may encapsulate the EAT in thepayload of the packet.

In addition, the broadcast transmitter 72 may encapsulate informationfor identifying data of the packet payload in a packet header. Further,information encapsulated in the packet header may be informationindicating that the packet is a packet including the emergency alertinformation.

The broadcast transmitter 72 inserts the generated EAT or emergencyalert packet into the physical layer frame (S105). Specifically, thebroadcast transmitter 72 inserts the EAT or emergency alert packet intothe physical layer frame transmitted through the physical layer pipe. Inthis instance, the physical layer frame may include informationindicating that the frame includes the emergency alert information.

In response to the emergency alert information inserted into thephysical layer frame, the broadcast transmitter 72 transmits a broadcastsignal including the physical layer frame through a particular physicallayer pipe (S107). In an embodiment, the particular physical layer pipemay be a physical layer pipe designated to transmit only the emergencyalert information. In another embodiment, the particular physical layerpipe may be a physical layer pipe that transmits signaling informationfor a broadcast service or data for common use applied to a plurality ofbroadcast services. In another embodiment, the particular physical layerpipe may be a physical layer pipe that transmits information necessaryfor service scanning including at least one of configuration informationof a broadcast stream, brief broadcast service information, andcomponent information. In another embodiment, the particular physicallayer pipe may be a general physical layer pipe, use of which has notbeen designated.

FIG. 61 is a flowchart illustrating an operation method of the broadcastreceiver 70 according to an embodiment of the present invention.

The broadcast receiver 70 receives the broadcast signal including theemergency alert information through the physical layer pipe (S201). Inan embodiment, the physical layer pipe may be a physical layer pipedesignated to transmit only the emergency alert information. In anotherembodiment, the particular physical layer pipe may be a physical layerpipe that transmits signaling information for a broadcast service ordata for common use applied to a plurality of broadcast services. Inanother embodiment, the particular physical layer pipe may be a physicallayer pipe that transmits at least one of configuration information of abroadcast stream, brief broadcast service information, and componentinformation. In another embodiment, the particular physical layer pipemay be a general physical layer pipe, use of which has not beendesignated.

The broadcast receiver 70 extracts the physical layer frame includingthe emergency alert information from the received broadcast signal(S203). In an embodiment, the physical layer frame may include an EAT.In this case, the EAT may include only minimum information for acquiringthe emergency alert information. In another embodiment, the physicallayer frame may include an emergency alert packet. The broadcastreceiver 70 acquires the emergency alert information by decoding theextracted physical layer frame (S205). Specifically, the broadcastreceiver 70 acquires the emergency alert information by decoding the EATor the emergency alert packet included in the physical layer frame. Inan embodiment, the broadcast receiver 70 may decode the physical layerframe based on particular information of the EAT or a header of theemergency alert packet. In another embodiment, the broadcast receiver 70may decode the physical layer frame based on information acquired bydecoding the EAT. Specifically, the broadcast receiver 70 may identifythe physical layer frame including the emergency alert information fromthe EAT, and decode the identified physical layer frame.

The broadcast receiver 70 determines whether the acquired emergencyalert information includes related service information (S207).Specifically, the broadcast receiver 70 determines whether informationabout related content which is related to the emergency alertinformation is included. Here, the related content may be one ofreal-time content and NRT content.

When the related content is determined to be present, the broadcastreceiver 70 determines whether the acquired related content informationis real-time content (S209). Specifically, the broadcast receiver 70determines whether content related to the emergency alert information isreal-time content or NRT content. Here, the real-time content may be A/Vcontent. Whether content is real-time content may be determined based onparticular information of the EAT. Alternatively, whether content isreal-time content may be determined based on information included in thepacket header.

Upon determining that the related content is real-time content, thebroadcast receiver 70 acquires the related content by decoding thephysical layer frame included in the received broadcast signal (S211).Specifically, the emergency alert information may include pathinformation that allows the related content to be acquired. Therefore,the broadcast receiver 70 may acquire content by identifying thephysical layer frame including the related content based on theinformation.

However, when the related content is determined to be NRT content, thebroadcast receiver 70 extracts path information for acquiring the NRTcontent (S215). The information for acquiring the NRT content may beaddress information. For example, the information may be URIinformation.

The broadcast receiver 70 acquires an NRT service through an IPcommunication unit based on the extracted path information (S217).Specifically, the broadcast receiver 70 acquires the NRT service throughthe broadband network using the address information.

The broadcast receiver 70 provides the acquired emergency alertinformation together with the related service (S213). Specifically, thebroadcast receiver 70 outputs the emergency alert information togetherwith the related service. In this instance, the related service may beone of a real-time service or an NRT service.

Meanwhile, signaling information for broadcast services in the broadcasttransmitter is transmitted to the physical layer by being included in apayload of the link layer packet, and the physical layer may configurethe physical layer packet by means of one or more link layer packets,map the physical layer packet into a specific data pipe (that is, PLP)and then transmit the physical layer packet to a receiving side througha coding and modulation process. In the present invention, the packet ofthe link layer may be referred to as a generic packet, and the packet ofthe physical layer may be referred to as a baseband packet.

Particularly, as one embodiment of the present invention, the emergencyalert message and/or the emergency alert related signaling informationis packetized into the link layer packet, and the link layer packet isagain packetized into the physical layer packet, mapped into a specificdata pipe and then transmitted to the broadcast receiver through thecoding and modulation process.

If a structure of the link layer packet that enables transmission ofsignaling information is defined in the system, the structure of thecorresponding packet is used as one embodiment of the present invention.At this time, as one embodiment, the existing field or a new field isused to transmit signaling information indicating that the correspondingpacket is an emergency alert related packet.

Generally, it is convenient that the signaling information related tothe emergency alert message is transmitted at one time, and thesignaling information may quickly be delivered to the broadcastreceiver. However, if there is no dedicated data path that can transmitemergency alert information in view of a structure of the system, or fora structure that is difficult to transmit every kind of emergency alertinformation at one time, a method for transmitting emergency alertrelated information through classification and segmentation of theemergency alert related information based on a certain reference may beused.

FIG. 62 illustrates a conceptual view of a link layer packet accordingto one embodiment of the present invention. Referring to FIG. 62, thelink layer packet includes a link layer packet header and a link layerpacket payload. For convenience of description, the link layer packetheader will be used to refer to “header”, and the link layer packetpayload will be used to refer to “payload”.

A header 210 of FIG. 62 may be divided into a fixed header of 1 byte andan extended header of a variable length.

FIG. 64 illustrates a header structure of FIG. 63 as a syntax format,and relates to the same as that of FIG. 63.

Therefore, each field of the link layer header will be described withreference to FIGS. 63 and 64.

That is, a packet type field (3 bits) of the fixed header indicates atype of data transmitted to the corresponding packet.

For example, if a value of a packet_type field is ‘000’, it indicatesdata of IPv4 transmitted to the corresponding packet. If the value ofthe packet type field is ‘010’, it indicates data of a header compressedIP packet transmitted to the corresponding packet.

And, if the value of a packet type field is ‘110’, it indicates datatransmitted to the corresponding packet is signaling information (orsignaling data). The signaling information may be either a signalingtable (or descriptor) or a signaling packet. The signaling table mayinclude a signaling table/table section included in DVB_SI (serviceinformation), PSI/PSIP, NRT (Non Real Time), ATSC 2.0, and MH(Mobile/Handheld), which exist conventionally.

In the present invention, the case where the value of the packet typefield is ‘110’ will be described in detail.

That is, if the value of the packet type field is ‘110’, fields of thefixed header and fields of the extended header, which are subsequent toa payload_config field, are varied depending on a value of thepayload_config field (1 bit). That is, information signaled to the fixedheader and information signaled to the extended header are determineddepending on the value of the payload_config field. The payload_configfield may be referred to as a packet configuration (PC) field.

One embodiment indicates whether the signaling information is segmentedby the upper layer and then provided to the link layer. According to oneembodiment, if the value of the payload_config field is ‘0’, thesignaling information is provided without being segmented by the upperlayer, and if the value of the payload_config field is ‘1’, thesignaling information is provided after being segmented by the upperlayer.

If the value of the payload_config field is ‘0’, a concatenation_countfield of 4 bits is included in the fixed header. Also, the extendedheader includes a signaling_class field of 3 bits, an information_typefield of 3 bits, and a signaling_format field of 2 bits. The extendedfield further includes a payload_length_part field of a variable lengthdepending on a value of the signaling_format field.

If the value of the payload_config field is ‘1’, an LI field of 1 bitand a segment_ID field of 3 bits are included in the fixed header. Also,the extended header includes a segment_sequence_number field of 4 bits,a segment_length_ID field of 4 bits, a signaling_class field of 3 bits,an information_type field of 3 bits, and a signaling_format field of 2bits, or includes a segment_sequence_number field of 4 bits and asegment_length_ID field of 4 bits, or includes a segment_sequence_numberfield of 4 bits and a last_segment_length field of 12 bits.

The concatenation_count field (4 bits) corresponds to a count field ofFIG. 64, and one embodiment of the present invention indicates how manylink layer packets through which signaling information provided by theupper layer is transmitted are used. Alternatively, the field mayindicate how many kinds of individual signaling information configureone payload.

The signaling_class field (3 bits) indicates a type of the signalinginformation included in the corresponding link layer packet, especiallya payload of the corresponding link layer packet.

FIG. 65 illustrates an example of a type of signaling informationdefined depending on a value of a signaling_class field according to thepresent invention.

For example, if the value of the signaling_class field is ‘000’, itindicates that the corresponding packet includes signaling information(for example, SLT) for channel scan and service acquisition. If thevalue of the signaling_class field is ‘001’, it indicates that thecorresponding packet includes signaling information for emergency alert.If the value of the signaling_class field is ‘010’, it indicates thatthe corresponding packet includes signaling information for headercompression.

In the present invention, if the value of the signaling_class field is‘001’, it indicates that the corresponding packet includes signalinginformation for emergency alert. However, this is one embodiment forassisting understanding of the present invention, and a reserved valueof the signaling_class field may be used to indicate that thecorresponding packet includes signaling information for emergency alert.

If the type of the signaling information transmitted to thecorresponding packet is determined by the value of the signaling_classfield, the information_type field indicates a type of data (that is,emergency alert information) transmitted to the payload of thecorresponding packet regarding the determined signaling information.Also, detailed information may additionally be included depending on thetype of the data.

In the present invention, if the value of the signaling_class field is001, the corresponding packet will be referred to as an emergency alertpacket.

FIG. 66 illustrates an example of meanings defined depending on a valueof the information_type field of the emergency alert packet according tothe present invention.

If the value of the information_type field is ‘000’, it indicates thatthe emergency alert message is transmitted to a payload of thecorresponding emergency alert packet. If the value of theinformation_type field is ‘001’, it indicates that link (or connection)information of the emergency alert message is transmitted to the payloadof the corresponding emergency alert packet. If the value of theinformation_type field is ‘010’, it indicates that information forautomatic channel tuning is transmitted to the payload of thecorresponding emergency alert packet. If the value of theinformation_type field is ‘011’, it indicates that emergency alertrelated NRT service information is transmitted to the payload of thecorresponding emergency alert packet.

And, if the value of the information_type field is ‘111’, it indicatesthat wake_up indication information is transmitted to the payload of thecorresponding emergency alert packet. The wake_up indication informationis required to indicate whether the corresponding emergency alertmessage needs a wake-up function. That is, the wake-up indicationinformation is required to support a wake-up function of the broadcastreceiver during the occurrence of disaster. The wake-up function meansthat the broadcast receiver should forcibly be switched to an activemode when an emergency alert message is issued, which is serious enoughto switch a sleeping mode (or standby mode) to the active mode eventhough the broadcast receiver is in the sleeping mode (or standby mode).In order to support the wake-up function, the broadcast receiver shouldcontinue to monitor a broadcast signal even in case of the sleepingmode, and should know how the occurrence of disaster is emergent, asquickly as possible.

In FIG. 66, the value allocated to the information_type field and themeaning of the value are embodiments for assisting understanding of thepresent invention, and addition and deletion of information included inthe information_type field may easily be varied by the person withordinary skill in the art. Therefore, the present invention will not belimited to the aforementioned embodiments. That is, if a procedurerelated to emergency alert is additionally provided later, a reservedvalue of the information_type field may be used to transmit the packetrelated to the corresponding procedure.

The signaling format field indicates a format of signaling informationfor emergency alert included in the corresponding packet as oneembodiment. Examples of the format that may be indicated by thesignaling format field may include a section table such as EAT, adescriptor within an EAT, and XML. For example, if the correspondingsignaling information has its length value in the same manner as thesection table and the descriptor, a separate length field may not berequired. However, a separate length field may be required in case ofsignaling information having no separate length value. In case of thesignaling information having no separate length value, apayload_length_part field (length field in FIG. 64) is used to indicatea length as one embodiment. In this case, the payload_length partincludes length fields equivalent to the number of count fields as oneembodiment.

That is, if the value of the signaling format field is ‘1×’, thepayload_length_part field indicates a length of signaling informationincluded in the payload of the corresponding packet. At this time, thepayload length part may be a set of length fields indicating a length ofeach of signaling information which are concatenated.

Meanwhile, if a value of the PC field is ‘1’, that is, if signalinginformation for emergency alert is provided by the upper layer throughsegmentation, fields included in the extended header are determineddepending on a value of the LI field.

The LI (last segment indicator) field indicates whether thecorresponding segment is the last segment, as one embodiment.

If the value of the LI field is ‘0’, that is, if the correspondingsegment is not the last segment, the segment_ID field indicatesinformation for identifying the corresponding segment.

The segment_sequence_number field indicates the order of respectivesegments when the signaling information for emergency alert is segmentedby the upper layer.

If the value of the LI field is ‘0’ and the value of the segmentsequence_number field value is ‘0000’, that is, the first segment of thesignaling information for emergency alert, the extended header includesa segment_length_ID field of 4 bits, a signaling_class field of 3 bits,an information_type field of 3 bits, and a signaling_format field of 2bits. The segment_length_ID field indicates a length of the firstsegment as one embodiment. Details of the signaling_class field, theinformation_type field and the signaling_format field will be understoodwith reference to the aforementioned description.

If the value of the LI field is ‘0’ and the value of thesegment_sequence_number field value is not ‘0000’, that is, neither thefirst segment nor the last segment of the signaling information foremergency alert, the extended header includes a segment_sequence_numberfield of 4 bits and a segment_length_ID field of 4 bits. As oneembodiment, the segment_sequence_number field indicates a segment numberindicating an order of a corresponding segment of the signalinginformation for emergency alert, and the segment_length_ID fieldindicates a length of the corresponding segment. That is, according toone embodiment, the segment length ID field is used to indicate a lengthof each segment except the last one of a plurality of segments.

If the value of the LI field is ‘1’, that is, the last segment, theextended header includes a segment_sequence_number field of 4 bits and alast_segment_length field of 12 bits. As one embodiment, thesegment_sequence_number field indicates a number of the last segment,and the last_segment_length field indicates a length of the lastsegment.

Therefore, when the signaling information for emergency alert issegmented, the signaling information for emergency alert may becompleted in such a manner that the broadcast receiver sequentiallycombines segments having the same segment ID by using the above fields.

FIG. 67 illustrates a syntax of an example of fields included in apayload of a link layer packet when a value of a packet_type field of acorresponding link layer packet header according to the presentinvention is ‘110’ and a value of an information_type field value is‘000’. That is, FIG. 67 illustrates an example of a syntax when thepayload of the corresponding link layer packet includes an emergencyalert message of the signaling information for emergency alert.

The emergency alert message is intended to mainly deliver a CAP message,and the payload of the link layer packet directly includes the CAPmessage. At this time, a concatenation method supported by a packetstructure of a link layer may be used to transmit several emergencyalert messages. In this case, the value of the payload_config field isset to ‘0’ and the value of the count field signals the number ofemergency alert messages, as one embodiment. Also, when the emergencyalert message is delivered using the link layer packet, versioninformation of the corresponding emergency alert message is given torepeatedly process the emergency alert message.

Each field of the payload of the link layer packet for transmitting theemergency alert message in FIG. 67 will be described as follows.

An EAS_message_id field (32 bits) indicates an identifier foridentifying each emergency alert message. As one embodiment, eachemergency alert message has an identifier identified from another one.

An EAS_mesage_encoding_type field (4 bits) indicates encoding typeinformation of the emergency alert message. For example, if a value ofthe EAS_message_encoding_type field is ‘000’, it indicates that anencoding type of the emergency alert message (or EAS message) has notbeen specified. If the value of the EAS_message_encoding_type field is‘001’, it indicates that the emergency alert message has not beenencoded. If the value of the EAS_message_encoding type field is ‘010’,it indicates that the emergency alert message has been encoded by aDEFLATE algorithm. If a new encoding method is used later, a reservedvalue of the EAS_message_encoding_type field may be used to indicate thenew encoding method.

An EAS_message_version field (4 bits) indicates version information ofthe corresponding emergency alert message. As one embodiment of thepresent invention, the version information included in theEAS_message_version field is used to determine whether to process theemergency alert messages having the same EAS_message_id. In the presentinvention, a value increased as much as 1 whenever a new emergency alertmessage is generated is given to the EAS_message_version field. In thiscase, if the value of the EAS_message_version field is high, itindicates a new emergency alert message. And, if the value of theEAS_message_version field reaches a maximum value, next value has ‘0’.If the version information of the emergency alert message can beidentified through the EAS_message_id field, the EAS_message_versionfield may be omitted.

An EAS_message_protocol field (4 bits) indicates a protocol of acorresponding emergency alert message. If the emergency alert message isa CAP message, the EAS_message_protocol field indicates a protocol ofthe CAP message as one embodiment. Also, if another protocol other thanthe protocol of the CAP message is used, the EAS_message_protocol fieldindicates the corresponding protocol. For example, theEAS_message_protocol field may be used for interworking of the emergencyalert message with another network such as a mobile network.

An EAS_message_length field (12 bits) indicates a length of an emergencyalert message actually included in a payload of a corresponding packet.An emergency alert message which is intended to be actually transmittedis transmitted through an EAS_message_bytes( ) field. That is, theEAS_message_bytes( ) field transmits the emergency alert message as muchas a length corresponding to a value of the EAS_message_length field.

FIG. 68 is a flowchart illustrating one embodiment of a method forreceiving and processing an emergency alert message in a broadcastreceiver according to the present invention. Particularly, FIG. 68illustrates one embodiment of a processing method when an emergencyalert message is received by being included in a payload of a link layerpacket in the same manner as FIG. 67.

That is, if a packet for emergency alert is received (S301), anidentifier of the emergency alert message is identified (S302). Thepacket received in the above step is the link layer packet decapsulatedfrom the physical layer packet, and it is identified whether the packetis a packet for emergency alert, especially a packet for transmitting anemergency alert message, by using information signaled to the header ofthe link layer packet as one embodiment. The identifier of the emergencyalert message is identified using the EAS_message_id field included inthe payload of the corresponding packet as one embodiment.

If the identifier of the emergency alert message is identified in thestep S302, it is identified whether the emergency alert message (thatis, EAS message) included in the payload of the corresponding packet iseffective (S303). If it is identified that the emergency alert messageis effective, version information of the emergency alert message isidentified (S304). That is, if it is identified that the emergency alertmessage is effective, the version information is identified using theEAS_message_version field included in the payload of the correspondingpacket. It is identified whether the corresponding emergency alertmessage is the updated message or the message which has beenconventionally received, based on the identified version information(S305). If the corresponding emergency alert message is a message of anew version, a decoding type and a protocol of the correspondingemergency alert message are identified using theEAS_message_encoding_type field and the EAS_message_protocol field ofthe payload of the corresponding packet (S306). The correspondingemergency alert message is processed in accordance with the identifieddecoding type and protocol (S307). However, if it is identified that theemergency alert message is not effective in the step S303, or if it isidentified that the corresponding emergency alert message is not newversion in the step S305, the packet received in the step S301 isdisregarded (S308). That is, if the received emergency alert message isnot effective or if the corresponding emergency alert message is not newversion newer than the emergency alert message which has beenconventionally received, the corresponding packet is disregarded and mayreturn to a standby state for receiving another packet.

FIG. 69 is a syntax illustrating examples of fields included in apayload of a corresponding link layer packet when a packet_type fieldvalue of the link layer packet header according to the present inventionindicates ‘110’, a signaling_class field value indicates ‘001’ and aninformation_type field value indicates ‘001’. That is, FIG. 49 is anexample of a syntax when a payload of a corresponding link layer packetincludes link or connection information of an emergency alert messageamong signaling information for emergency alert.

FIG. 69 illustrates an example of transmitting link or connectioninformation of the emergency alert message to the payload of the linklayer packet when the emergency alert message is transmitted through aseparate path due to a lack of bandwidth.

Each field of the payload of the link layer packet for transmitting linkor connection information of the emergency alert message in FIG. 69 willbe described as follows.

Since an EAS_message_id field (32 bits), an EAS_message_encoding_typefield (4 bits), an EAS_message_version field (4 bits), and anEAS_message_protocol field (4 bits) mean the EAS_message_id field, theEAS_message_encoding_type field, the EAS_message_version field and theEAS_message_protocol field of FIG. 67, their detailed description willbe understood with reference to FIG. 67 and thus will be omitted here.

Meanwhile, in FIG. 69, a message_link_type field (4 bits) indicates atype of link information for acquiring the emergency alert message whenthe emergency alert message is transmitted through another path otherthan the payload of the corresponding packet.

For example, if a value of the message_link_type field is ‘0000’, itindicates that IP datagram of the emergency alert message is transmittedthrough a data pipe (that is, PLP). That is, this case may be applied toa case where the emergency alert message is transmitted through a datapipe, which is located within a channel to which the correspondingpacket is received, in the form of IP datagram. In this case, accessinformation for accessing IP datagram of the emergency alert message isadditionally signaled. The access information includes at least one ofan IP address, a UDP port number, and identification information of thecorresponding data pipe as one embodiment.

That is, if the value of the message_link_type field is ‘0000’, thecorresponding payload includes an IP address field, a UDP_port_numfield, and a DP_id field.

The IP address field (32 or 128 bits) indicates an IP address of IPv4 oran IP address of IPv6 of the IP datagram of the emergency alert message,and the UDP_port_num field (16 bits) indicates a UDP port number of theIP datagram of the emergency alert message. The DP_id field (8 bits)indicates an identifier of a data pipe that transmits the IP datagram ofthe emergency alert message.

If the value of message_link_type field is ‘0001’, it indicates that theemergency alert message is transmitted through another channel not thechannel to which the corresponding packet is transmitted. In this case,access information for accessing the emergency alert message transmittedto another channel is additionally signaled. The access informationincludes at least one of channel information, data pipe identificationinformation, and service information as one embodiment.

That is, if the value of the message_link_type field is ‘0001’, thecorresponding payload includes an EAS_channel_number field, an EAS_DP_idfield, and an EAS_service_id field.

The EAS_channel_number field (8 bits) indicates channel information towhich the emergency alert message is transmitted. In this case, thechannel information may be a frequency number, or may be a major channelnumber and a minor channel number. That is, the EAS_channel_number fieldindicates a corresponding channel number when the emergency informationmessage is received from another channel not the channel currentlyreceived by the broadcast receiver. If the channel number is relatedwith the frequency number, the corresponding field may be replaced withthe frequency number.

The EAS_DP_id field (8 bits) indicates an identifier of a data pipe thattransmits the emergency alert message from a channel signaled to the EASchannel number field value. The EAS_DP_id field is optionally used. Forexample, if there is a separate path in the corresponding channelinstead of the data pipe to which the emergency alert message istransmitted, the corresponding field may not be provided additionally.

The EAS_service_id field (16 bits) indicates an identifier of a servicethat includes the emergency alert message. That is, when severalservices are transmitted to one channel, the EAS_service_id fieldindicates an identifier of a service for acquiring the emergency alertmessage. If it is required to acquire a separate service in receivingthe emergency alert message, the field may not be provided additionally.

If the value of the message_link_type field is ‘0010’, it indicates thatthe emergency alert message is transmitted through a broadband when thebroadcast receiver is connected to the broadband. If the value of themessage_link_type field is ‘0010’, a broadband_link_info( ) field of avariable length is provided additionally. The broadband_link_info( )field indicates link information for the emergency alert messagetransmitted through the broadband.

If the value of the message_link_type field is ‘0011’, it indicates thatthe emergency alert message is transmitted through another network (forexample, mobile network) not a broadcast network and a broadbandnetwork. If the value of the message_link_type field ‘0011’, anexternal_network_information ( ) field of a variable length is providedadditionally. The external_network_information ( ) field indicates linkinformation for the emergency alert message transmitted through anothernetwork such as a mobile network and information for the correspondingnetwork. The other values of the message_link_type field are reservedfor future use. Therefore, the remaining values may be used laterdepending on new link. Also, if the emergency alert message istransmitted through a network not the broadcast network, the remainingvalues may be used to transmit additional emergency alert message.

FIG. 70 is a flowchart illustrating another embodiment of a method forreceiving and processing an emergency alert message in a broadcastreceiver according to the present invention. Particularly, FIG. 70illustrates an embodiment of a processing method when link informationof an emergency alert message is received by being included in a payloadof a link layer packet in the same manner as FIG. 69.

That is, if a packet for emergency alert is received (S401), anidentifier of the emergency alert message is identified (S402). Thepacket received in the above step is the link layer packet decapsulatedfrom the physical layer packet, and it is identified whether the packetis a packet for emergency alert, especially a packet for transmittinglink information of the emergency alert message, by using informationsignaled to the header of the link layer packet as one embodiment. Theidentifier of the emergency alert message is identified using theEAS_message_id field included in the payload of the corresponding packetas one embodiment.

If the identifier of the emergency alert message is identified in thestep S402, it is identified whether the emergency alert message (thatis, EAS message) is effective (S403). If it is identified that theemergency alert message is effective, version information of theemergency alert message is identified using the EAS_message_versionfield included in the payload of the corresponding packet (S404). It isidentified whether the corresponding emergency alert message is theupdated message or the message which has been conventionally received,based on the identified version information (S405). If the correspondingemergency alert message is a message of a new version, a decoding typeand a protocol of the corresponding emergency alert message areidentified using the EAS_message_encoding_type field and theEAS_message_protocol field which are included in the payload of thecorresponding packet (S406).

Connection or link information to which the corresponding emergencyalert message is transmitted is identified using the message_link_typefield included in the payload of the corresponding packet (S407). It isidentified whether a network that transmits the emergency alert messageis an available network based on the connection or link informationidentified in the step S407 (S408). If it is identified that thecorresponding network is the available network in the step S408, theemergency alert message is received using access information included inthe payload of the corresponding packet (S409). That is, if thecorresponding connection or link information is an effective network ora link that may be linked by the broadcast receiver, the emergency alertmessage is received using access information of the corresponding link.

For example, if a value of the message_link_type field is ‘0000’, thatis, if the emergency alert message is received through a data pipe,which is located within a channel to which the corresponding packet isreceived, in the form of IP datagram, the access information may be atleast one of an IP address, a UDP port number, and identificationinformation of the data pipe.

If the value of the message_link_type field is ‘0001’, that is, if theemergency alert message is received through another channel not thechannel to which the corresponding packet is received, the accessinformation may be at least one of channel information, data pipeidentification information, and service identification information.

If the value of the message_link_type field is ‘0010’, that is, if theemergency alert message is received through a broadband, the accessinformation may be acquired from a broadband_link_info( ) field includedin the payload of the corresponding packet.

If the value of the message_link_type field is ‘0011’, that is, if theemergency alert message is received through another network (forexample, mobile network) not a broadcast network and a broadbandnetwork, the access information may be acquired from anexternal_network_information ( ) field included in the packet of thecorresponding packet.

If the emergency alert message is received in the step S409, thereceived emergency alert message is processed in accordance with thedecoding type and protocol identified in the step S406 (S410). However,if it is identified that the emergency alert message is not effective inthe step S403, if it is identified that the corresponding emergencyalert message is not new version in the step S405, or if it isidentified that the corresponding network is not available network inthe step S408, the packet received in the step S401 is disregarded(S411). That is, if the link for transmitting the emergency alertmessage is not effective, if it is not possible to access thecorresponding link, or if the corresponding emergency alert message isnot new version newer than the emergency alert message which has beenconventionally received, the corresponding packet is disregarded and mayreturn to a standby state for receiving another packet.

FIG. 71 is a syntax illustrating examples of fields included in apayload of a corresponding link layer packet when a packet_type fieldvalue of the link layer packet header according to the present inventionindicates ‘110’, a signaling_class field value indicates ‘001’ and aninformation_type field value indicates ‘010’. That is, FIG. 71 is anexample of a syntax when a payload of a corresponding link layer packetincludes information for automatic tuning to a channel for transmittingcontents related to an emergency alert message among signalinginformation for emergency alert.

In other words, FIG. 71 illustrates an example of transmitting automatictuning information for automatic tuning from a current channel to achannel, to which emergency alert related contents are transmitted, to apayload of a link layer packet in a broadcast receiver when audio/videocontents related to emergency alert are transmitted simultaneously withthe emergency alert message.

Each field of the payload of the link layer packet for transmittingautomatic tuning information related to emergency alert in FIG. 71 willbe described as follows.

A num_associated_EAS_messages field (8 bits) indicates the number ofemergency alert messages related to channel tuning information. A ‘for’loop (or message identification loop) is performed as much as a value ofthe num_associated_EAS_messages field, whereby identificationinformation of the related emergency alert message is provided. To thisend, an associated_EAS_message_id field (32 bits) is included in the‘for’ loop. That is, the associated_EAS_message_id field indicates anidentifier of each emergency alert message related to automatic tuninginformation transmitted to a current packet. Theassociated_EAS_message_id field may be used to identify whether thebroadcast receiver has received the emergency alert message for channeltuning earlier than the tuning information.

An automatic_tuning_channel_number field (8 bits) indicates channelinformation which should be tuned to receive audio/video contentsrelated to emergency alert. In this case, the channel information may bea frequency number, or may be a major channel number and a minor channelnumber. That is, the automatic_tuning_channel_number field may indicatea channel number for transmitting audio/video contents related toemergency alert. If the channel number is related with the frequencynumber, the corresponding field may be replaced with the frequencynumber or may be used together with the frequency number.

An automatic_tuning_DP_id field (8 bits) indicates an identifier of adata pipe (that is, physical layer pipe) that transmits audio/videocontents related to emergency alert from a channel signaled to theautomatic_tuning_channel_number field.

An automatic_tuning_service_id field (16 bits) indicates an identifierof a service for acquiring audio/video contents related to emergencyalert.

FIG. 72 is a flowchart illustrating still another embodiment of a methodfor receiving and processing an emergency alert message in a broadcastreceiver according to the present invention. Particularly, FIG. 72illustrates an embodiment of a processing method when automatic tuninginformation related to emergency alert is received by being included ina payload of a link layer packet in the same manner as FIG. 51.

That is, if a packet for emergency alert is received (S501), anidentifier of the emergency alert message is identified (S502). Thepacket received in the above step is the link layer packet decapsulatedfrom the physical layer packet, and it is identified whether the packetis a packet for emergency alert, especially a packet for transmittinginformation for automatic tuning, by using information signaled to theheader of the link layer packet as one embodiment. The identifier of theemergency alert message is identified using theassociated_EAS_message_id field included in the payload of thecorresponding packet as one embodiment.

If the identifier of the emergency alert message is identified in thestep S502, it is identified whether the emergency alert message (thatis, EAS message) is effective (S503). As one embodiment of the presentinvention, when the packet is received, it is identified whether therelated emergency alert message is received earlier than the packet,using the associated_EAS_message_id field, and if not so, it may beidentified that the corresponding emergency alert message is noteffective. In this case, the corresponding packet is disregarded withoutbeing processed as one embodiment.

If it is identified that the emergency alert message is effective,tuning information is acquired from the payload of the correspondingpacket (S504). The tuning information may be acquired from at least oneof the automatic_tuning_channel_number field, the automatic_tuning_DP_idfield, and the automatic_tuning_service_id field.

Then, it is identified whether channel tuning is ready (S505), and if itis identified that channel tuning is ready, a current channel isautomatically tuned to a channel for transmitting emergency alertrelated audio/video contents based on the channel information, wherebyemergency alert service is acquired (S506). If the current channel isthe channel for transmitting emergency alert related audio/videocontents indicated by the channel information, the current channel ismaintained without channel tuning. However, if it is identified that theemergency alert message is not effective in the step S503, or if it isidentified that channel tuning is not ready in the step S505, the packetreceived in the step S501 is disregarded and returns to a standby statefor receiving another packet (S507).

Meanwhile, as one embodiment of the present invention, if the receivedpacket is a packet for emergency alert, especially a packet fortransmitting information for automatic tuning, it may indicate that anautomatic tuning flag is enabled. Also, if the corresponding packet isreceived, it is identified whether the related emergency alert messageis received earlier than the packet, and if the related emergency alertmessage is not received earlier than the packet, the correspondingpacket is disregarded. To this end, a list of emergency alert messagesrelated to channel information to be currently tuned may be transmittedto the payload of the corresponding packet by using theassociated_EAS_message_id field.

FIG. 73 is a syntax illustrating examples of fields included in apayload of a corresponding link layer packet when a packet_type fieldvalue of the link layer packet header according to the present inventionindicates ‘1110’, a signaling_class field value indicates ‘001’ and aninformation_type field value indicates ‘011’. That is, FIG. 73 is anexample of a syntax when a payload of a corresponding link layer packetincludes NRT service information related to emergency alert amongsignaling information for emergency alert.

Each field of the payload of the link layer packet for transmitting NRTservice information related to emergency alert in FIG. 73 will bedescribed as follows.

A num_associated_EAS_messages field (8 bits) indicates the number ofemergency alert messages related to channel tuning information. A ‘for’loop (or message identification loop) is performed as much as a value ofthe num_associated_EAS_messages field, whereby identificationinformation of the related emergency alert message is provided. To thisend, an associated_EAS_message_id field (32 bits) is included in the‘for’ loop. That is, the associated_EAS_message_id field indicates anidentifier of each emergency alert message related to automatic tuninginformation which is transmitted. The associated_EAS_message_id fieldmay be used to identify whether the broadcast receiver has received theemergency alert message for channel tuning earlier than the channeltuning information.

An EAS_NRT_service_id field (16 bits) indicates an identifier of NRTservice corresponding to a case where NRT contents and data related tothe received emergency alert message are transmitted, that is, a casewhere EAS_NRT_flag is enabled.

FIG. 74 is a flowchart illustrating further still another embodiment ofa method for receiving and processing an emergency alert message in abroadcast receiver according to the present invention. Particularly,FIG. 74 illustrates an embodiment of a processing method when NRTservice information related to emergency alert is received by beingincluded in a payload of a link layer packet in the same manner as FIG.73.

That is, if a corresponding packet is received, the broadcast receivermay identify an identifier of NRT service and enter a procedure ofacquiring NRT service.

That is, if a packet for emergency alert is received (S601), anidentifier of the emergency alert message is identified (S602). Thepacket received in the above step is the link layer packet decapsulatedfrom the physical layer packet, and it is identified whether the packetis a packet for emergency alert, especially a packet for transmittingNRT service information related to emergency alert, by using informationsignaled to the header of the link layer packet as one embodiment. Theidentifier of the emergency alert message is identified using theassociated_EAS_message_id field included in the payload of thecorresponding packet as one embodiment.

If the identifier of the emergency alert message is identified in thestep S602, it is identified whether the emergency alert message (thatis, EAS message) is effective (S603). As one embodiment of the presentinvention, when the packet is received, it is identified whether therelated emergency alert message is received earlier than the packet,using the associated_EAS_message_id field, and if not so, it may beidentified that the corresponding emergency alert message is noteffective. In this case, the corresponding packet is disregarded withoutbeing processed as one embodiment (S606).

If it is identified that the emergency alert message is effective, anidentifier of the NRT service is identified from the payload of thecorresponding packet (S604). The identifier of the NRT service may beidentified using the EAS_NRT_service_id field included in the payload ofthe packet.

If the identifier of the NRT service is identified in the step S604, thecorresponding NRT service is acquired based on the identified identifier(S605).

Meanwhile, as one embodiment of the present invention, if the receivedpacket is a packet for emergency alert, especially a packet fortransmitting NRT service information related to emergency alert, it isidentified whether the related emergency alert message is receivedearlier than the NRT service information, and if the related emergencyalert message is not received earlier than the NRT service, thecorresponding packet is disregarded. To this end, a list of emergencyalert messages related to channel information to be currently tuned maybe transmitted to the payload of the corresponding packet by using theassociated_EAS_message_id field.

Meanwhile, the method for processing emergency alert information, asdescribed with reference to FIGS. 62 to 74, may be performed by any oneof the emergency alert systems of FIGS. 53 to 56 and FIG. 58.

FIGS. 75 to 77 illustrate various embodiments of a receiving apparatusof a next generation broadcasting system for processing emergency alertinformation in accordance with the present invention.

FIG. 75 is a schematic block diagram illustrating a receiving apparatusof a next generation broadcasting system according to one embodiment ofthe present invention.

A receiving apparatus M100 according to one embodiment of the presentinvention includes a receiving module M1110, a controller M1150, and anInternet protocol (IP) communication module M1130. The receiving moduleM1110 includes a channel synchronizer M1111, a channel equalizer M1115,and a channel decoder M1113. The controller M1150 may include asignaling decoder M1151, a baseband operation controller M1157, aservice map DB M1161, a transport packet interface M1153, a broadbandpacket interface M1155, a common protocol stack M1159, a servicesignaling channel processing buffer & parser M1163, an A/V processorM1165, a service guide processor M1167, an application processor M1169,and/or a service guide DB M1171.

In FIG. 75, the channel synchronizer M1111 of the receiving module M1110synchronizes symbol frequency with timing to decode a signal receivedfrom a baseband. In this case, the baseband indicates an area where abroadcast signal is transmitted and received.

The channel equalizer M1115 performs channel equalization on thereceived signal. The channel equalizer M1115 serves to compensate forthe received signal when the received signal is distorted due tomultipath, Doppler effect, etc.

The channel decoder M1113 recovers the received signal to a transportframe which is meaningful. The channel decoder M1113 performs forwarderror correction (FEC) for data included in the received signal or thetransport frame.

The signaling decoder M1151 extracts and decodes signaling data includedin the received signal. In this case, the signaling data includesignaling data, which will be described later, and/or serviceinformation (SI). Also, the signaling data may include an emergencyalert message or emergency alert related signaling information.

The baseband operation controller M1157 controls signal processing atthe baseband.

The service map DB M1161 stores signaling data and/or serviceinformation therein. The service map DB M1161 may store signaling datatransmitted by being included in a broadcast signal and/or signalingdata transmitted by being included in a broadband packet.

The transport packet interface M1153 extracts a transport packet fromthe transport frame or the broadcast signal. In this case, the transportpacket is a link layer packet acquired by decapsulation of a basebandpacket included in the transport frame as one embodiment.

The transport packet interface M1153 extracts signaling data or IPdatagram from the transport packet. The broadband packet interface M1155receives a broadcasting related packet through the broadband. Thebroadband packet interface M1155 extracts the packet acquired throughthe broadband, and combines or extracts signaling data or A/V data fromthe corresponding packet.

The common protocol stack M1159 processes the received packet inaccordance with a protocol included in a protocol stack. For example,the common protocol stack M1159 may process the received packet in eachprotocol in accordance with the aforementioned method.

The service signaling channel processing buffer & parser M1163 extractssignaling data included in the received packet. The service signalingchannel processing buffer & parser M1163 extracts signaling informationrelated to scan and/or acquisition of services and/or contents from theIP datagram, and parses the extracted signaling information. Thesignaling data may exist at a given location or channel within thereceived packet. This location or channel may be referred to as aservice signaling channel. For example, the service signaling channelmay have a specific IP address, a UDP port number, a transport sessionidentifier, etc. The receiver may recognize data transmitted to thespecific IP address, the UDP port number and the transport session assignaling data.

The A/V processor M1165 performs decoding and presentation processingfor received audio and video data.

The service guide processor M1167 extracts announcement information fromthe received signal, manages a service guide DB M1171, and provides aservice guide.

The application processor M1169 extracts application data and/orapplication related information included in the received packet andprocesses the extracted application data and application relatedinformation.

The service guide DB M1171 stores service guide data therein.

Also, the controller M1150 processes emergency alert related informationaccording to the present invention, which is received from the linklayer packet, as one embodiment. To this end, the controller M1150 mayfurther include an emergency alert processor (not shown), and thetransport packet interface M1153 may process the emergency alert relatedinformation according to the present invention. In FIG. 75, thetransport packet interface M1153 processes the emergency alert relatedinformation as one embodiment. That is, the transport packet interfaceM1153 extracts the transport packet from the transport frame (orphysical layer frame) or the broadcast signal. At this time, thetransport packet may be a physical layer packet or a link layer packet.If the transport packet is a physical layer packet, the link layerpacket is acquired by decapsulation of the physical layer packet as oneembodiment. The link layer packet depends on the structures of FIGS. 62to 64 as one embodiment. This is one embodiment for assistingunderstanding of the present invention, and since the link layer packetstructure according to the present invention may be modified by adesigner, the present invention is not limited to the aforementionedembodiment.

The transport packet interface M1153 may identify that data received inthe link layer packet using each field included in the header of thelink layer packet as shown in FIGS. 62 to 66 is signaling informationand especially is a packet that includes signaling information foremergency alert. In addition, the transport packet interface M1153 mayidentify whether the payload of the link layer packet includes anemergency alert message of signaling information for emergency alert,link information of an emergency alert message, emergency alert relatedautomatic tuning information, emergency alert related NRT serviceinformation, or wake-up indication information. The method and steps forthis identification have been described in detail as above and thustheir description will be omitted herein.

If it is identified that the payload of the corresponding link layerpacket includes the emergency alert message of signaling information foremergency alert, the transport packet interface M1153 processes theemergency alert message included in the corresponding payload withreference to each field included in the payload of the correspondingpacket as described with reference to FIGS. 67 and 68.

If it is identified that the payload of the corresponding link layerpacket includes link information of the emergency alert message ofsignaling information for emergency alert, the transport packetinterface M1153 acquires link information and/or access information foracquiring the emergency alert message with reference to each fieldincluded in the payload of the corresponding packet as described withreference to FIGS. 69 and 70, and receives and processes the emergencyalert message by using the acquired link information and/or accessinformation.

For example, if it is identified that the emergency alert message isreceived in the form of IP datagram through a data pipe within a channelto which the corresponding packet is received, the link and accessinformation may be at least one of an IP address, a UDP port number andidentification information of the data pipe. For another example, if itis identified that the emergency alert message is received throughanother channel not the channel to which the corresponding packet isreceived, the link and access information may be at least one of channelinformation, identification information of the data pipe, and serviceidentification information.

If it is identified that the payload of the corresponding link layerpacket includes emergency alert related automatic tuning information ofsignaling information for emergency alert, the transport packetinterface M1153 acquires tuning information, which will be tunedautomatically, with reference to each field included in the payload ofthe corresponding packet as described with reference to FIGS. 71 and 72,and controls channel tuning by using the acquired tuning information.

If it is identified that the payload of the corresponding link layerpacket includes emergency alert related NRT service information ofsignaling information for emergency alert, the transport packetinterface M1153 acquires emergency alert related NRT service informationwith reference to each field included in the payload of thecorresponding packet as described with reference to FIGS. 73 and 74, andacquires NRT service based on the acquired information.

FIG. 76 is a schematic block diagram illustrating a broadcast receiverof a next generation broadcasting system according to another embodimentof the present invention.

In the embodiment of FIG. 76, the broadcast receiver includes abroadcasting receiving module M2110, an Internet protocol (IP)communication module M2130, and a controller M2150.

The broadcasting receiving module M2110 may include a tuner, a physicalframe parser, and a physical layer controller.

The tuner extracts a physical frame by receiving a broadcast signalthrough a broadcast channel. The physical frame is a transport unit on aphysical layer. The physical frame parser acquires a link layer packetby parsing the received physical frame. For example, the physical frameparser acquires the link layer packet by decapsulation of a basebandpacket included in the physical frame as one embodiment. The link layerpacket may be referred to as a link layer frame, and a link layer packetparser may be referred to as a link layer frame parser. The physicallayer controller controls operations of the tuner and the physical frameparser. In one embodiment, the physical layer controller may control thetuner by using RF information of the broadcast channel. In more detail,if the physical layer controller transmits frequency information to thetuner, the tuner may acquire the physical frame corresponding to thereceived frequency information from the broadcast signal.

In another embodiment, the physical layer controller may control theoperation of the physical layer parser through an identifier of aphysical layer pipe. In more detail, the physical layer controllertransmits identifier information for identifying a specific one of aplurality of physical layer pipes to the physical frame parser. Thephysical frame parser may identify the physical layer pipe based on thereceived identifier information and acquire the link layer packet fromthe identified physical layer pipe.

The controller M2150 includes a link layer packet parser, an IP/UDPdatagram filter, a control engine, an ALC/LCT+ client, a timingcontroller, a DASH client, an ISO BMFF parser, and a media decoder.

The link layer packet parser extracts data from the link layer packet.In more detail, the link layer packet parser may acquire link layersignaling from the link layer packet. Also, the link layer packet parsermay acquire IP/UDP datagram from the link layer packet.

The IP/UDP datagram filter filters a specific one from the IP/UDPdatagram received from the link layer packet parser.

The ALC/LCT+ client processes an application layer transport packet. Theapplication layer transport packet may include an ALC/LCT+ packet. Inmore detail, the ALC/LCT+ client may generate one or more ISO BMFF mediafile format objects by collecting a plurality of application layertransport packets.

The timing controller processes a packet that includes system timeinformation, and controls a system clock in accordance with theprocessed result.

The DASH client processes real time streaming or adaptive mediastreaming. In more detail, the DASH client may acquire a DASH segment byprocessing adaptive media streaming based on HTTP. At this time, theDASH segment may be a format of ISO BMFF object.

The ISO BMFF parser extracts audio/video data from the ISO BMFF objectreceived from the DASH client. At this time, the ISO BMFF parser mayextract the audio/video data in a unit of an access unit. Also, the ISOBMFF parser may acquire timing information for audio/video from the ISOBMFF object.

The media decoder decodes the received audio and video data. Also, themedia decoder performs presentation for the decoded result through amedia output terminal.

The control engine serves as an interface between the respectivemodules. In more detail, the control engine may control the operation ofeach module by transmitting a parameter required for the operation ofeach module.

The Internet protocol communication module M2130 may include an HTTPaccess client. The HTTP access client may transmit and receive a requestto and from an HTTP server, or may transmit and receive a response tothe request to and from the HTTP server.

As one embodiment of the present invention, the emergency alert relatedinformation according to the present invention, which is received fromthe link layer packet parser to the link layer packet, is processed. Asanother embodiment, the present invention may further include anemergency alert processor (not shown). The link layer packet acquired bythe physical layer packet parser depends on the structures of FIGS. 62to 64 as one embodiment. This is one embodiment for assistingunderstanding of the present invention, and since the link layer packetstructure according to the present invention may be modified by adesigner, the present invention is not limited to the aforementionedembodiment.

The link layer packet parser may identify that data received in the linklayer packet using each field included in the header of the link layerpacket as shown in FIGS. 62 to 66 is signaling information andespecially is a packet that includes signaling information for emergencyalert. In addition, the link layer packet parser may identify whetherthe payload of the link layer packet includes an emergency alert messageof signaling information for emergency alert, link information of anemergency alert message, emergency alert related automatic tuninginformation, emergency alert related NRT service information, or wake-upindication information. The method and steps for this identificationhave been described in detail as above and thus their description willbe omitted herein.

If it is identified that the payload of the corresponding link layerpacket includes the emergency alert message of signaling information foremergency alert, the link layer packet parser processes the emergencyalert message included in the corresponding payload with reference toeach field included in the payload of the corresponding packet asdescribed with reference to FIGS. 67 and 68.

If it is identified that the payload of the corresponding link layerpacket includes link information of the emergency alert message ofsignaling information for emergency alert, the link layer packet parseracquires link information and/or access information for acquiring theemergency alert message with reference to each field included in thepayload of the corresponding packet as described with reference to FIGS.69 and 70, and receives and processes the emergency alert message byusing the acquired link information and/or access information.

If it is identified that the payload of the corresponding link layerpacket includes emergency alert related automatic tuning information ofsignaling information for emergency alert, the link layer packet parseracquires tuning information, which will be tuned automatically, withreference to each field included in the payload of the correspondingpacket as described with reference to FIGS. 71 and 72, and controlschannel tuning by using the acquired tuning information.

If it is identified that the payload of the corresponding link layerpacket includes emergency alert related NRT service information ofsignaling information for emergency alert, the link layer packet parseracquires emergency alert related NRT service information with referenceto each field included in the payload of the corresponding packet asdescribed with reference to FIGS. 73 and 74, and acquires NRT servicebased on the acquired information.

FIG. 77 is a schematic block diagram illustrating a broadcast receiverof a next generation broadcasting system according to still anotherembodiment of the present invention.

In the embodiment of FIG. 77, the broadcast receiver M3100 includes abroadcasting receiving module M3110, an Internet protocol (IP)communication module M3130, and a controller M3150.

The broadcasting receiving module M3110 may include one or a pluralityof processors for performing each of a plurality of functions performedby the broadcasting receiving module M3110, one or a plurality ofcircuits, and one or a plurality of hardware modules. In more detail,the broadcasting receiving module M3110 may be a system on chip (SOC) inwhich a plurality of semiconductor parts are integrated into one. Atthis time, the SOC may be a semiconductor obtained by combining variousmultimedia parts, such as graphic, audio, video, and modem, with aprocessor and DRAM. The broadcasting receiving module M3110 may includea physical layer module M3119 and a physical layer IP frame moduleM3117. The physical layer module M3119 receives and processes abroadcasting related signal through a broadcast channel of a broadcastnetwork. The physical layer IP frame module M3117 converts a data packetsuch as IP datagram acquired from the physical layer module M3119 to aspecific frame. For example, the physical layer IP frame module M3117may convert the IP datagram to a link layer frame, a link layer packet,or GSE.

The IP communication module M3130 may include one or a plurality ofprocessors for performing each of a plurality of functions performed bythe IP communication module M3130, one or a plurality of circuits, andone or a plurality of hardware modules. In more detail, the IPcommunication module M3130 may be a system on chip (SOC) in which aplurality of semiconductor parts are integrated into one. At this time,the SOC may be a semiconductor obtained by combining various multimediaparts, such as graphic, audio, video, and modem, with a processor andDRAM. The IP communication module M3130 may include an Internet accesscontrol module M3131. The Internet access control module M3131 controlsthe operation of the broadcast receiver M3100 for acquiring at least oneof services, contents and signaling data through an Internetcommunication network (broadband).

The controller M3150 may include one or a plurality of processors forperforming each of a plurality of functions performed by the controllerM3150, one or a plurality of circuits, and one or a plurality ofhardware modules. In more detail, the controller M3150 may be a systemon chip (SOC) in which a plurality of semiconductor parts are integratedinto one. At this time, the SOC may be a semiconductor obtained bycombining various multimedia parts, such as graphic, audio, video, andmodem, with a processor and DRAM.

The controller M3150 may include at least one of a signaling decoderM3151, a service map database M3161, a service signaling channel parserM3163, an application signaling parser M3166, an emergency alertsignaling parser M3168, a targeting signaling parser M3170, a targetingprocessor M3173, an A/V processor M3161, an emergency alert processorM3162, an application processor M3169, a scheduled streaming decoderM3181, a file decoder M3182, a user request streaming decoder M3183, afile database, a component synchronizer M3185, a service/contentacquisition controller M3187, a redistribution module M3189, a devicemanager M3193, and a data sharing module M3191.

The service/content acquisition controller M3187 controls the operationof the receiver for acquiring services, contents, and signaling datarelated to services or contents, which are acquired through a broadcastnetwork or Internet communication network.

The signaling decoder M3151 decodes signaling information.

The service signaling parser M3163 parses service signaling information.

The application signaling parser M3166 extracts and parses signalinginformation related to services. At this time, the signaling informationrelated to services may be signaling information related to servicescan. Also, the signaling information related to services may besignaling information related to contents provided through services.

The emergency alert signaling parser M3168 extracts and parses emergencyalert related signaling information.

The targeting signaling parser M3170 extracts and parses information forpersonalizing services or contents or information for signalingtargeting information.

The targeting processor M3173 processes information for personalizingservices or contents.

The emergency alert processor M3162 processes emergency alert relatedsignaling information.

The application processor M3169 controls running of application andapplication related information. In more detail, the applicationprocessor M3169 processes a state of a downloaded application and adisplay parameter.

The A/V processor M3161 processes a rendering related operation ofaudio/video on the basis of decoded audio or video, application data,etc.

The scheduled streaming decoder M3181 previously decodes scheduledstreaming which is a content streamed in accordance with a scheduledetermined by a content provider such as a broadcasting station.

The file decoder M3182 decodes downloaded files. Particularly, the filedecoder M3182 decodes files downloaded through a broadband.

The user request streaming decoder M3183 decodes an on demand commandprovided by a user request.

The file database stores files therein. In more detail, the filedatabase may store files downloaded through the broadband.

The component synchronizer M3185 synchronizes contents or services. Inmore detail, the component synchronizer M3185 performs synchronizationfor a play time of a content acquired through at least one of thescheduled streaming decoder M3181, the file decoder M3182 and the userrequest streaming decoder M3183.

The service/content acquisition controller M3187 controls the operationof the receiver for acquiring at least one of services, contents, andsignaling information related to services or contents.

The redistribution module M3189 performs an operation for supportingacquisition of at least one of service, content, service relatedinformation and content related information if service or content is notreceived through a broadcast network. In more detail, the redistributionmodule M3189 may request an external management device M3300 of at leastone of service, content, service related information and content relatedinformation. At this time, the external management device M3300 may be acontent server.

The device manager M3193 manages an interworking external device. Inmore detail, the device manager M3193 may perform at least one ofaddition, deletion and update of the external device. Also, the externaldevice may enable connection and data exchange with the broadcastreceiver M3100.

The data sharing module M3191 performs a data transmission operationbetween the broadcast receiver M3100 and the external device, andprocesses exchange related information. In more detail, the data sharingmodule M3191 may transmit A/V data or signaling information to theexternal device. Also, the data sharing module M3191 may receive A/Vdata or signaling information from the external device.

Meanwhile, the physical layer IP frame module 117 converts a basebandpacket included in a physical layer frame to a link layer packet throughdecapsulation as one embodiment. As one embodiment, the emergency alertsignaling parser M3168 extracts and parses emergency alert relatedsignaling information from the link layer packet, and the emergencyalert processor M3162 processes the parsed emergency alert relatedsignaling information.

The link layer packet parsed by the emergency alert signaling parserM3168 depends on the structures of FIGS. 62 to 64 as one embodiment.This is one embodiment for assisting understanding of the presentinvention, and since the link layer packet structure according to thepresent invention may be modified by a designer, the present inventionis not limited to the aforementioned embodiment.

The emergency alert signaling parser M3168 may identify that datareceived in the link layer packet using each field included in theheader of the link layer packet as shown in FIGS. 62 to 66 is signalinginformation and especially is a packet that includes signalinginformation for emergency alert. In addition, the emergency alertsignaling parser M3168 may identify whether the payload of the linklayer packet includes an emergency alert message of signalinginformation for emergency alert, link information of an emergency alertmessage, emergency alert related automatic tuning information, emergencyalert related NRT service information, or wake-up indicationinformation. The method and steps for this identification have beendescribed in detail as above and thus their description will be omittedherein.

If it is identified that the payload of the corresponding link layerpacket includes the emergency alert message of signaling information foremergency alert, the emergency alert processor M3162 processes theemergency alert message included in the corresponding payload withreference to each field included in the payload of the correspondingpacket as described with reference to FIGS. 67 and 68.

If it is identified that the payload of the corresponding link layerpacket includes link information of the emergency alert message ofsignaling information for emergency alert, the emergency alert processorM3162 acquires link information and/or access information for acquiringthe emergency alert message with reference to each field included in thepayload of the corresponding packet as described with reference to FIGS.69 and 70, and receives and processes the emergency alert message byusing the acquired link information and/or access information.

If it is identified that the payload of the corresponding link layerpacket includes emergency alert related automatic tuning information ofsignaling information for emergency alert, the emergency alert processorM3162 acquires tuning information, which will be tuned automatically,with reference to each field included in the payload of thecorresponding packet as described with reference to FIGS. 71 and 72, andcontrols channel tuning by using the acquired tuning information.

If it is identified that the payload of the corresponding link layerpacket includes emergency alert related NRT service information ofsignaling information for emergency alert, the emergency alert processorM3162 acquires emergency alert related NRT service information withreference to each field included in the payload of the correspondingpacket as described with reference to FIGS. 73 and 74, and acquires NRTservice based on the acquired information.

FIG. 78 is a diagram illustrating an FIC according to an embodiment ofthe present invention.

In terrestrial broadcasting, in general, one frequency is used by onebroadcaster. However, according to the present embodiment, one frequencymay be shared by one or more broadcasters. Hereinafter, a descriptionwill be given of a method of sharing one frequency by one or morebroadcasters based on low level signaling information.

The low level signaling information is signaling information thatsupports bootstrapping of rapid channel scanning and service acquisitionby a receiver. The low level signaling information may include a fastinformation table (FIT) (or an SLT). The low level signaling informationmay be transmitted through a dedicated channel. For example, thededicated channel may include an FIC. The FIC may include informationnecessary for acquisition of a service transmitted on a currentfrequency for rapid channel reception and scanning. The FIC may be adedicated channel for cross-layer information that allows rapid serviceacquisition and channel scanning. This information may mainly includechannel binding information between DPs and services of respectivebroadcasters.

The signaling information may include a plurality of low level signalinginformation. For example, a plurality of low level signaling informationmay be present within a dedicated channel. However, each broadcaster maytransmit one low level signaling information (or FIT). Alternatively,each broadcaster may transmit at least one low level signalinginformation (or FIT).

The low level signaling information may include information foridentifying each broadcaster. For example, the information foridentifying each broadcaster may be a provider_id field. Here, eachbroadcaster is identified by the provider_id field, and services of onebroadcaster may have the same provider_id field value.

Therefore, even when one frequency is shared by a plurality ofbroadcasters, a receiver may receive and/or acquire a low level signalfrom a particular broadcaster based on a provider_id field.

Hereinafter, details of the FIC will be described. The FIC, the FIT, andthe SLT may indicate the low level signaling information.

Referring to the figure, the FIC may include at least one of anFIC_protocol_version field, a broadcaststream_id field, a num_servicesfield, a service_id field, a service_data_version field, aservice_channel_number field, a service_category field, a partition_idfield, a short_service_name_length field, a short_service_name field, aservice_status field, an sp_indicator field, an IP_version_flag field,an SSC_source_IP_address_flag field, a num_min_capability field, amin_capability_type field, a min_capability_value field, anSSC_source_IP_address field, an SSC_destination_IP address field, anSSC_destintion_UDP_port field, an SSC_TSI field, an SSC_DP_ID field, anum_service_level_descriptors field, a service_level_descriptor( )field, a num_FIC_level_descriptors field, and/or anFIC_level_descriptor( ) field.

The FIC_protocol_version field may indicate a version of a structure ofthe FIC.

The broadcaststream_id field may indicate an ID of an overall broadcaststream.

The num_services field may indicate the number of services having atleast one component within each broadcast stream. Each “for” loopsubsequent to the num_services field may include information about eachservice.

The service_id field may indicate an ID for identifying a service.

A value of the service_data_version field may be incremented when aservice entry for a service is changed within an FIC or when a signalingtable for a service transmitted through a service signaling channel ischanged. The service_data_version field allows a receiver to monitor anFIC, and enables the receiver to detect whether signaling for serviceshas changed.

The service_channel_number field may indicate a channel number of acorresponding service.

The service_category field may indicate a category of a correspondingservice.

The partition_id field may indicate an ID of a partition in which aservice is broadcast. For example, the partition_id field may indicatean ID for identifying a broadcaster related to the service.

The short_service_name_length field may indicate the number of bytepairs in the short_service_name field. A value of theshort_service_name_length field may be indicated by “m” in the number ofbits for the short_service_name field. When there is no short name in aservice, the short_service_name_length field may have a value of “0”.The short_service_name_length field may have a value of 3 bits.

The short_service_name field may indicate a short name of a service.Each character of the short name may be encoded in UTF-8 [ ]. When thereis an odd number of bytes in the short name, the second byte of the lastbyte pair for a pair count indicated by the short_service_name_lengthfield may include “0x00”. (short_service_name field indicates the shortname of the Service, each character of which shall be encoded per UTF-8[ ]. When there is an odd number of bytes in the short name, the secondbyte of the last of the byte pair per the pair count indicated by theshort_service_name_length field shall contain 0x00)

The service_status field may indicate a status of a service. Forexample, the service_status field may indicate whether the service is inan “active” status or a “suspended” state. In addition, theservice_status field may indicate whether the service is in a “hidden”status or a “shown” status.

The sp_indicator field may indicate a service protection flag. Thesp_indicator field may indicate whether to interpret at least oneprotected component for significant presentation.

The IP_version_flag field may indicate a version of an Internetprotocol. For example, when the IP_version_flag field has a value of“0”, the IP_version_flag field may indicate that theSSC_source_IP_address field and the SSC_destination_IP address fieldhave IPv4 addresses. When the IP_version_flag field has a value of “1”,the IP_version_flag field may indicate that the SSC_source_IP_addressfield and the SSC_destination_IP_address field have IPv6 addresses.

The SSC_source_IP_address_flag field may indicate whether a servicesignaling channel source IP address value for a service is present.

The num_min_capability field may indicate the number of minimumcapabilities of each service. Each of at least one “for” loop subsequentto the num_min_capability field may include information related to acapability.

The min_capability_type field may indicate a type of a minimumcapability.

The min_capability_value field may indicate a value of a minimumcapability.

The SSC_source_IP_address field may be present when theSSC_source_IP_address_flag field has a value of “1”. In addition, theSSC_source_IP_address field may not be present when the SSC_source_IPaddress_flag field has a value of “0”. When the SSC_source_IP addressfield is present, the SSC_source_IP address field may include source IPaddresses of all IP datagrams that transmit a signal for a correspondingservice. Conditional use of a 128-bit address version of this fieldenables IPv6 to be used in the future.

The SSC_destination_IP_address field may include destination IPaddresses of all IP datagrams transmitting a signal for a correspondingservice. Conditional use of a 128-bit address version of this fieldenables IPv6 to be used in the future.

The SSC_destintion_UDP_port field may indicate a destination UDP portnumber for a UDP/IP stream that transmits a stream for a correspondingservice.

The SSC_TSI field may indicate a transport session identifier (TSI) ofan LCT channel (or an LCT session) that transmits signaling tables for acorresponding service.

The SSC_DP_ID field may indicate an ID ofa DP (or a physical DP)including signaling tables for a corresponding service. The DP may bethe most robust pipe within a partition.

The num_service_level_descriptors field may indicate the number ofservice level descriptors for a corresponding service. Each of at leastone “for” loop subsequent to the num_service_level_descriptors field mayinclude at least one service level descriptor.

The service_level_descriptor( ) field may include at least onedescriptor that provides additional information for a service.

The num_FIC_level_descriptors field may indicate the number ofdescriptors of an FIC level for a corresponding FIC.

The FIC_level_descriptor( ) field may include at least one descriptorthat provides additional information for an FIC.

FIG. 79 is a diagram illustrating a service category according to anembodiment of the present invention.

Low level signaling information and/or an FIC may include theservice_category field. The service_category field may indicate acategory of a corresponding service.

For example, the service_category field may indicate one of anaudio/video (A/V) service, an audio service, an electronic service guide(ESG) service, a content on demand (CoD) service, an app-based service,and/or an emergency alert message (EAM) service (or an emergency alertsignaling (EAS) service).

For example, when a value of the service_category field indicates “0x00or informative only”, the value of the service_category field may betreated as an informative description of a category of a service. Inaddition, a receiver needs to investigate a component mapping table(CMT) that refers to a service map table (SMT) to identify an actualcategory of a service transmitted through an ATSC 3.0 service. Withregard to services having a video and/or audio component, the servicesmay include an NTP timebase component.

In addition, when a value of the service_category field indicates“0x01”, the service_category field may indicate that a service categoryis an A/V service. In addition, when a value of the service_categoryfield indicates “0x02”, the service_category field may indicate that aservice category is an audio service. In addition, when a value of theservice_category field indicates “0x03”, the service_category field mayindicate that a service category is an app-based service. In addition,when a value of the service_category field indicates “0x08”, theservice_category field may indicate that a service category is an ESGservice.

FIG. 80 is a diagram illustrating a form in which one frequency isshared by two broadcasters according to an embodiment of the presentinvention.

An emergency alert message (or disaster information, EAS message) may bedelivered through a dedicated PHY pipe such as an EAC, or transmittedthrough link layer signaling (or low level signaling) of a general PHYpipe (or DP, PLP). Alternatively, the emergency alert message may betransmitted in the form of a service.

When the emergency alert message is transmitted through the general PHYpipe, the emergency alert message may be transmitted through a separatepipe separated for each broadcaster, or the emergency alert message maybe transmitted through one pipe.

When the emergency alert message is transmitted through a separate pipeseparated for each broadcaster, the receiver may distinguish theemergency alert message for each broadcaster.

However, when emergency alert messages of several broadcasters aretransmitted together through one pipe, the receiver cannot distinguishthe emergency alert messages for respective broadcasters. Further, whenemergency alert messages are transmitted through the dedicated PHY pipe,emergency alert messages transmitted from several broadcasters are mixedand transmitted through one pipe, and thus the receiver cannot filterthe emergency alert messages for the respective broadcasters.

Referring to the figure, one frequency may be shared by broadcaster Aand broadcaster B.

At least one service may be transmitted through one frequency. Forexample, broadcaster A may transmit service 1 and/or service 2. Inaddition, broadcaster B may transmit service k−1 and/or service k.

In addition, a plurality of low level signaling information (forexample, the FIC and the SLT) for services may be transmitted throughone frequency. For example, low level signaling information may includefirst low level signaling information for services transmitted frombroadcaster A and second low level signaling information for servicestransmitted from broadcaster B. The first low level signalinginformation may include a partition_id field that identifies broadcasterA. For example, a value of the partition_id field included in the firstlow level signaling information may indicate “1”. In addition, thesecond low level signaling information may include a partition_id fieldthat identifies broadcaster B. For example, a value of the partition_idfield included in the second low level signaling information mayindicate “2”.

Therefore, when one frequency is shared by two broadcasters (broadcasterA and broadcaster B), a partition_id field according to an embodiment ofthe present invention may be used as a factor for identifying abroadcaster.

Referring to the figure, one frequency is shared by two broadcasters,and each of the broadcasters may be identified by a partition_id field.When a user is viewing a service (e.g., service 1) of broadcaster A inwhich a value of the partition_id field is recognized as “1”, thereceiver may need to receive and process an emergency alert messagedelivered by broadcaster A.

Forms in which an emergency alert message is delivered may be sorted asbelow.

First, an emergency alert message may be transmitted through one pipe (adedicated pipe or a general pipe) for each broadcaster.

For example, when one frequency is used by one broadcaster, the receivermay know that the emergency alert message is transmitted from onebroadcaster irrespective of a form of a pipe (e.g., a dedicated pipe, ageneral pipe, etc.). In addition, when the emergency alert message istransmitted through a separate pipe for each broadcaster, the receivermay know that the emergency alert message is transmitted from onebroadcaster.

Second, emergency alert messages of two or more broadcasters may betransmitted through one pipe (a dedicated pipe or a general pipe).

For example, when several broadcasters share and use a frequency,emergency alert messages of two or more broadcasters may be transmittedthrough one pipe. When the emergency alert messages are transmittedthrough the dedicated pipe or a particular pipe, the receiver cannotdistinguish the emergency alert messages for the respectivebroadcasters.

To solve the above-described problem, an embodiment of the presentinvention may provide a method of filtering an emergency alert messagetransmitted through one pipe for each broadcaster. To this end, mappinginformation in which each emergency alert message is mapped to eachbroadcaster needs to be present.

For example, the partition_id field of the low level signalinginformation (the FIC or the SLT) according to the embodiment of thepresent invention may be used as the mapping information in which eachemergency alert message is mapped to each broadcaster.

FIG. 81 is a diagram illustrating Emergency_Alert_Table( ) according toan embodiment of the present invention.

Referring to the figure, an emergency alert table(Emergency_Alert_Table( )) may include at least one of a table_id field,a table_id_extension field, an EAT_protocol_version field, anautomatic_tuning_flag field, a num_EAS_messages field, anautomatic_tuning_channel_number field, an automatic_DP_id field, anautomatic_service_id field, an EAS_message_id field, anEAS_IP_version_flag field, an EAS_message_transfer_type field, anEAS_message_encoding_type field, an EAS_NRT_flag field, anEAS_message_length field, an EAS_message_bytes( ) field, an IP_addressfield, a UDP_port_num field, a DP_id field, and/or an NRT_service_idfield.

The table_id field identifies a type of a current table. A broadcastreceiver may identify that a present table is an emergency alert tableusing the table_id field.

The table_id_extension field includes the EAT_protocol_version field. Inaddition, when a structure of an emergency alert table is changed, theEAT_rotocol_version field identifies version information thereof.

The automatic_tuning_flag field (1 bit) indicates whether toautomatically change a channel.

The num_EAS_messages field (7 bits) indicates the number of emergencyalert messages included in an emergency alert table.

When the automatic_tuning_flag field indicates “1”, that is, automaticchannel conversion, the emergency alert table further includes theautomatic_tuning_channel_number field, the automatic_DP_id field, andthe automatic_service_id field.

The automatic_tuning_channel_number field (8 bits) indicates informationabout a channel which includes content related to emergency alertinformation.

The automatic_DP_id field (8 bits) indicates information for identifyinga DP, that is, a PHY pipe including A/V content related to the emergencyalert message.

The automatic_service_id field (16 bits) indicates service IDinformation of content related to the emergency alert message.

Further, a “for” loop repeated a number of times corresponding to avalue of the num_EAS_messages field includes the EAS_message_id field,the EAS_IP_version_flag field, the EAS_message_transfer_type field, theEAS_message_encoding_type field, and the EAS_NRT_flag field.

The EAS_message_id field (32 bits) indicates a unique ID for identifyingan emergency alert message. A value of this field may be changed when aprevious emergency alert message is updated or canceled. As anotherexample, this field may be extracted from a CAP message ID.

The EAS_IP_version_flag field (1 bit) indicates an IP version in whichthe emergency alert table is transmitted. The IP_address field includesan IPv4 address when a value of this field is “0”, and includes an IPv6address when a value of this field is “1”.

The EAS_message_transfer_type field (3 bits) indicates a transmissiontype of an emergency alert table. In a specific example, theEAS_message_transfer_type field may indicate that a transmission type ofan EAS message (emergency alert message) has not been specified. In thiscase, the EAS_message_transfer_type field may have a value of “0x00”.

In another example, the EAS_message_transfer_type field may indicatethat a transmission type of an EAS message (emergency alert message) isa type in which the emergency alert message is not included. In thiscase, the EAS_message_transfer_type field may have a value of “0x01”.

In another example, the EAS_message_transfer_type field may indicatethat the EAS message (emergency alert message) is included andtransferred in an EAT. In this case, the EAS_message_transfer_type fieldmay have a value of “0x02”.

Further, when the EAS_message_transfer_type field has the value of“0x02”, an emergency alert table including the EAS message (emergencyalert message) may additionally indicate a length of the EAS message(emergency alert message). In this case, information indicating thelength of the EAS message (emergency alert message) may correspond tothe EAS_message_length field. The EAS_message_length field maycorrespond to 12 bits. In addition, the EAS_message_bytes( ) fieldsubsequent to the EAS_message_length field transmits an emergency alertmessage including emergency alert content corresponding to a length of avalue of the EAS_message_length field.

In another example, the EAS_message_transfer_type field may indicatethat the EAS message (emergency alert message) is transmitted through aPHY pipe in the form of an IP datagram. In this case, theEAS_message_transfer_type field may have a value of “0x03”.

When the EAS_message_transfer_type field has the value of “0x03”, theemergency alert table may additionally include at least one of theIP_address field (32 or 128 bits) that indicates IP address informationfor acquiring an IP datagram which transmits the EAS message (emergencyalert message), the UDP_port_num field (16 bits) that indicates a UDPport number, and the DP_id field (8 bits) that indicates identificationinformation of a physical layer frame (that is, a PLP or a DP) in whichthe EAS message is transmitted.

Meanwhile, the EAS_message_encoding_type field (3 bits) indicates anencoding type of an emergency alert message. In a specific example, theEAS_message_encoding_type field may indicate that an encoding type of anemergency alert message has not been specified. In this case, theEAS_message_encoding_type field may have a value of “0x00”.

In another example, the EAS_message_encoding_type field may indicatethat an emergency alert message has not been encoded. In this case, theEAS_message_encoding_type field may have a value of “0x01”.

In another example, the EAS_message_encoding_type field may indicatethat an emergency alert message has been encoded by a DEFLATE algorithm.The DEFLATE algorithm is a lossless compression data format. In thiscase, the EAS_message_encoding_type field may have a value of “0x02”.

When the EAS_NRT_flag field has a value of “I”, the emergency alerttable includes the NRT_service_id field. The NRT_service_id field (16bits) indicates identification information for identifying an NRTservice related to an emergency alert.

The emergency alert table may further include the partition_id field.The partition_id field may indicate an ID of a partition in which aservice is broadcast. For example, the partition_id field may indicatean ID for identifying a broadcaster related to a service.

For example, an emergency alert table according to an embodiment of thepresent invention may include at least one emergency alert messageprovided by at least one broadcaster. In addition, the emergency alertmessage may include the partition_id field.

The receiver may receive an emergency alert message from at least onebroadcaster. The receiver may filter an emergency alert messagedelivered by a broadcaster that provides a current channel/service basedon the partition_id field. Then, the receiver may express an emergencyalert message filtered for each broadcaster to the user.

FIG. 82 is a diagram illustrating a flow of a broadcast receiveraccording to an embodiment of the present invention.

The figure illustrates an operation flow of filtering an emergency alertmessage (or an EAS message) for each broadcaster by the broadcastreceiver.

The broadcast receiver according to the embodiment of the presentinvention may check a value of a partition_id field of the emergencyalert message (EAS message). Then, the broadcast receiver may verifywhether the value of the partition_id field of the emergency alertmessage (EAS message) is the same as a value of a partition_id field ofa currently viewed channel/service.

When the values are the same, the broadcast receiver may process theemergency alert message (EAS message). When the values are differentfrom each other, the broadcast receiver may discard the emergency alertmessage (EAS message).

Hereinafter, a detailed description will be given of the flowchart ofthe broadcast receiver.

The broadcast receiver may receive a packet for the emergency alertmessage using a broadcast receiving unit and/or a controller (CS820010).

Then, the broadcast receiver may check a value of the partition_id fieldof the emergency alert message using the controller (CS820020).

Then, the broadcast receiver may verify whether the value of thepartition_id field of the emergency alert message is the same as thevalue of the partition_id field of the currently viewed channel/service(CS820030).

When the values are the same, the broadcast receiver may check an ID ofthe emergency alert message using the controller (CS820040). Forexample, the broadcast receiver may check the ID of the emergency alertmessage based on the EAS_message_id field.

When the values are different from each other, the broadcast receivermay discard the packet for the emergency alert message (CS820100).

Then, the broadcast receiver may verify whether the emergency alertmessage which is included in a payload of the packet is a valid messageusing the controller (CS820050).

When the emergency alert message an invalid message, the broadcastreceiver may discard the packet for the emergency alert message(CS820100). That is, when the received emergency alert message isinvalid, the broadcast receiver may ignore the packet and return to areception standby state for another packet.

When the emergency alert message is a valid message, the broadcastreceiver may check version information of the emergency alert messageusing the controller (CS820060). For example, the broadcast receiver maycheck the version information of the emergency alert message based onthe EAS_message_version field.

Then, the broadcast receiver may verify whether the emergency alertmessage is an updated message or a previously received message using thecontroller (CS820070).

When the emergency alert message is the previously received message, thebroadcast receiver may discard the packet for the emergency alertmessage (CS820100). That is, when the received emergency alert messageis the previously received message, the broadcast receiver may ignorethe packet and return to a reception standby state for another packet.

When the emergency alert message is a message of a new version, thebroadcast receiver may check a decoding type and a protocol of theemergency alert message using the controller (CS820080). For example,the broadcast receiver may check the decoding type and the protocol ofthe emergency alert message based on the EAS_message_encoding_type fieldand the EAS_message_protocol field.

Then, the broadcast receiver may process the emergency alert messageaccording to the checked decoding type and protocol using the controller(CS820090).

FIG. 83 is a diagram illustrating a flow of a broadcast receiveraccording to an embodiment of the present invention.

When several broadcasters use one pipe (dedicated pipe or general pipe)for transmission of an emergency alert message (EAS message), two casesmay be sorted as below.

First, in a case in which the user views a channel of a broadcastertransmitting the emergency alert message (EAS message):

When a broadcaster of a currently viewed channel transmits the emergencyalert message (EAS message), the broadcast receiver may normally filterand/or receive the emergency alert message (EAS message) to inform theuser of an emergency situation.

Second, in a case in which the user does not view a channel of abroadcaster transmitting the emergency alert message (EAS message):

Even though broadcasters share a pipe for transmission of the emergencyalert message (EAS message), a broadcaster of a currently viewed channelmay not transmit the emergency alert message (EAS message). In thiscase, the broadcast receiver may receive the emergency alert message(EAS message) of another broadcaster other than the broadcaster of thecurrently viewed channel and inform the user of an emergency situation.

An operation flow of the broadcast receiver that supports the aboveoperation is as below.

The broadcast receiver may receive a packet for an emergency alertmessage using a broadcast receiving unit and/or a controller (CS830010).For example, a broadcast signal may include a plurality of emergencyalert tables transmitted by a plurality of broadcasters. A particularbroadcaster may not transmit an emergency alert table. In addition, anemergency alert table may include a plurality of emergency alertmessages. One emergency alert table may include a plurality of emergencyalert messages for a plurality of broadcasters. For example, therespective emergency alert messages may include partition_id fields forthe plurality of broadcasters.

Then, the broadcast receiver may verify whether an emergency alertmessage having a value of a partition_id field which indicates abroadcaster of a currently viewed channel is present among all emergencyalert messages (EAS messages) defined in an emergency alert table(Emergency_Alert_Table) using the controller (CS830015).

When there is no emergency alert message having the value of thepartition_id field which indicates the broadcaster of the currentlyviewed channel, the broadcast receiver may process the receivedemergency alert message (EAS message) without filtering. That is, thebroadcast receiver may proceed to CS830040. In this case, the broadcastreceiver needs to process all received emergency alert messages.

When there is an emergency alert message having the value of thepartition_id field which indicates the broadcaster of the currentlyviewed channel, the broadcast receiver may check the value of thepartition_id field of the emergency alert message using the controller(CS830020). For example, the broadcast receiver may check a value of apartition_id field with respect to each emergency alert message includedin an emergency alert table.

Then, the broadcast receiver may verify whether the value of thepartition_id field of the emergency alert message is the same as thevalue of the partition_id field of the currently viewed channel/serviceusing the controller (CS830030). That is, the broadcast receiver mayfilter and process the emergency alert message (EAS message) bycomparing the value of the partition_id field of the emergency alertmessage with the value of the partition_id field of the currently viewedchannel/service.

When the values are the same as a result of comparison, the broadcastreceiver may check an ID of the emergency alert message using thecontroller (CS830040). For example, the broadcast receiver may check theID of the emergency alert message based on the EAS_message_id field.

When the values are different from each other as a result of comparison,the broadcast receiver may discard the packet for the emergency alertmessage (CS830100).

Then, the broadcast receiver may verify whether the emergency alertmessage which is included in a payload of the packet is a valid messageusing the controller (CS830050).

When the emergency alert message is an invalid message, the broadcastreceiver may discard the packet for the emergency alert message(CS830100). That is, when the received emergency alert message isinvalid, the broadcast receiver may ignore the packet and return to areception standby state for another packet.

When the emergency alert message is a valid message, the broadcastreceiver may check version information of the emergency alert messageusing the controller (CS830060). For example, the broadcast receiver maycheck the version information of the emergency alert message based onthe EAS_message_version field.

Then, the broadcast receiver may verify whether the emergency alertmessage is an updated message or a previously received message using thecontroller (CS830070).

When the emergency alert message is the previously received message, thebroadcast receiver may discard the packet for the emergency alertmessage (CS830100). That is, when the received emergency alert messageis the previously received message, the broadcast receiver may ignorethe packet and return to a reception standby state for another packet.

When the emergency alert message is a message of a new version, thebroadcast receiver may check a decoding type and a protocol of theemergency alert message using the controller (CS830080). For example,the broadcast receiver may check the decoding type and the protocol ofthe emergency alert message based on the EAS_message_encoding_type fieldand the EAS_message_protocol field.

Then, the broadcast receiver may process the emergency alert messageaccording to the checked decoding type and protocol using the controller(CS830090).

Even when broadcaster A of a channel currently viewed by the user doesnot transmit an emergency alert message, the broadcast receiver may usean emergency alert table and/or an emergency alert message ofbroadcaster B which is transmitting the emergency alert message. In thisinstance, the emergency alert table transmitted by broadcaster B mayinclude an emergency alert message for broadcaster A in addition to anemergency alert message for broadcaster B. Therefore, the broadcastreceiver may provide an emergency alert message to the user on a currentchannel based on the emergency alert table and/or the emergency alertmessage of broadcaster B.

FIG. 84 is a diagram illustrating syntax related to an EAC added to PLSaccording to an embodiment of the present invention.

Hereinafter, a description will be given of a method that allowstransmission of a private data stream according to an embodiment of thepresent invention. For example, a description will be given of a methodof transmitting and/or receiving a WARN message according to anembodiment of the present invention.

An emergency alert message (or emergency alert data) according to anembodiment of the present invention may include the WARN message and/ora common alert protocol (CAP) message. The WARN message refers to adisaster broadcast message used in a disaster broadcast constructionsystem constructed by PBS (Public Broadcasting Service of the UnitedStates). In addition, an EAS message generally refers to a disastermessage used in disaster broadcasting. Further, the CAP message meansthat the EAS message is transmitted in a form of a CAP. Here, the CAPmessage and the EAS message may have the same meaning.

An embodiment of the present invention describes a method oftransmitting and/or receiving the WARN message through an EAC. Totransmit the WARN message through the EAC, PLS according to anembodiment of the present invention may include syntax related to theEAC.

The PLS according to the embodiment of the present invention may includeat least one of an EAC_Flag field, a num_EA_data field, an EA_data_Typefield, a WARN_data_version field, a WARN_data_target field, aWARN_data_version field, a WARN_data_target field, a WARN_data_Lengthfield, and/or a CAP_message_info( ) field.

The EAC_Flag field may indicate whether an EAC is present within acorresponding PHY frame (or a frame of a physical layer). When a valueof the EAC_Flag field is “true”, the EAC may be present. The num_EA_datafield may indicate the number of transmitted emergency alert messages(or emergency alert data). A “for” loop subsequent to the num_EA_datafield may include content related to emergency alert messages, thenumber of which is indicated by a value of the num_EA_data field.

The EA_data_Type field may indicate a type of an emergency alertmessage. A value of this field may be assigned as below, and a remainingvalue may be assigned based on a possibility that a new type may beadded in the future.

For example, when a value of the EA_data_Type field is “0”, a type of anemergency alert message may be “WARN only”. In this case, the emergencyalert message may include only the WARN message.

In addition, when a value of the EA_data_Type field is “I”, a type of anemergency alert message may be “WARN+CAP”. In this case, the emergencyalert message may include the WARN message and the CAP message.

In addition, when a value of the EA_data_Type field is “2”, a type of anemergency alert message may be “CAP only”. In this case, the emergencyalert message may include only the CAP message.

When a value of the EA_data_Type field is “0”, the PLS according to theembodiment of the present invention may include at least one of theWARN_data_version field and/or the WARN_data_target field.

The WARN_data_version field may indicate a version of a transmitted WARNmessage (or WARN data).

The WARN_data_target field may indicate target information of thetransmitted WARN message (or WARN data). For example, when a value ofthe WARN_data_target field is “0”, the target information of the WARNmessage (or WARN data) may indicate “Communities of Amber Alerts”. Inaddition, when a value of the WARN_data_target field is “I”, the targetinformation of the WARN message (or WARN data) may indicate “Imminentthreats to safety or life”. In addition, when a value of theWARN_data_target field is “2”, the target information of the WARNmessage (or WARN data) may indicate “Presidential Alerts viageographically-targeted”.

When a value of the EA_data_Type field is “I”, the PLS according to theembodiment of the present invention may include at least one of theWARN_data_version field, the WARN_data_target field, theWARN_data_Length field, and/or the CAP_message_info( ) field.

Content about the WARN_data_version field and the WARN_data_target fieldhas been described above.

The WARN_data_Length field may indicate length information of the WARNmessage. When a broadcast transmitter transmits both the WARN messageand the CAP message, the broadcast transmitter may transmit the WARNmessage having the corresponding length, and transmit a messagesubsequent to the data length as the CAP message.

The CAP_message_info( ) field may include CAP message information. Forexample, the CAP_message_info( ) field may include at least one of amessage_id field that identifies a CAP_message_info( ) field messageand/or a CAP message encoding type field that indicates an encoding typeof the CAP message.

When a value of the EA_data_Type field is “2”, the PLS according to theembodiment of the present invention may include the CAP_message_info( )field.

Content about the CAP_message_info( ) field has been described above.

FIG. 85 is a diagram illustrating a form in which only the WARN messageis transmitted through the EAC according to an embodiment of the presentinvention.

A broadcast transmitter according to an embodiment of the presentinvention may transmit PLS information.

PLS may include at least one of an EAC_Flag field, an EA_data_Typefield, a WARN_data_version field, and/or a WARN_data_target field.Content about signaling information included in the PLS has beendescribed above.

For example, the EAC_Flag field may have a value of“true” to indicatethat the EAC is present.

In addition, the EA_data_Type field may have a value of “00” to indicatethat a type of an emergency alert message is “WARN only”. In this case,the emergency alert message may include only a WARN message.

In addition, the WARN_data_version field may have a value of “1”.

In addition, the WARN_data_target field may have a value of “1” toindicate that target information of a WARN message (or WARN data) is“Imminent threats to safety or life”.

The broadcast transmitter according to the embodiment of the presentinvention may transmit an FIT (or SLT). For example, the FIT may betransmitted through an FIC. In addition, the FIT may be encapsulated inan IP/UDP datagram and transmitted.

The FIT is signaling information that supports bootstrapping of rapidchannel scanning and service acquisition by the receiver. The FIT mayinclude signaling information used to establish basic service listingand signaling information that provides discovery of a bootstrap of SLS.

For example, the FIT may include bootstrap information for SLSinformation of a service (Srv#1) and/or a service (Srv#1).

The broadcast transmitter according to the embodiment of the presentinvention may transmit a WARN message through a dedicated PLP. In thisinstance, the PLP designated to transmit the WARN message may bereferred to as an EAC. In other words, the EAC may be a dedicated PLPfor transmission of only a physical layer frame including the WARNmessage. Here, the physical layer frame may be a unit of datatransmitted through a physical layer. The physical layer may include oneor more PLPs, and the physical layer frame may be transmitted throughthe PLP.

The broadcast transmitter according to the embodiment of the presentinvention may transmit service data and SLS information for a service.

The service data may include at least one of a video component, an audiocomponent, and/or a captioning component. The service data may betransmitted through a ROUTE session. The ROUTE session may be identifiedthrough a destination IP address (dIP1), a destination port number(dPort1), and/or a source IP address (sIP1). In addition, the ROUTEsession may be transmitted through at least one PLP. For example, theROUTE session may be transmitted through one PLP (PLP#1).

The ROUTE session may include at least one LCT session (or LCT channel).Each LCT session may be identified by a TSI. Each of the videocomponent, the audio component, and the SLS information may betransmitted through the LCT session. For example, the video componentmay be transmitted through a first LCT session (tsi-v), the audiocomponent may be transmitted through a second LCT session (tsi-a), andthe SLS information may be transmitted through a third LCT session(tsi-sls).

SLS may be signaling that provides information for discovering andacquiring a service and a content component thereof. The SLS may includea USD, an S-LSID, and/or an MPD. The USD may be expressed as a USBD, andthe S-LSID may be expressed as a S-TSID.

The USD may include reference information of SLS for a service (Srv#1).

The MPD may include a period element. The period element may include afirst AdaptationSet element having information about at least one videocomponent and a second AdaptationSet element having information about atleast one audio component.

Each of the first AdaptationSet element and the second AdaptationSetelement may include a Representation element. For example, the firstAdaptationSet element may include a first Representation elementincluding information for a first Representation and a secondRepresentation element including information for a secondRepresentation. The second AdaptationSet element may include a thirdRepresentation element including information for a third Representationand a fourth Representation element including information for a fourthRepresentation.

The first Representation and the second Representation may beinterchanged. In addition, the third Representation and the fourthRepresentation may be interchanged.

Each Representation element may include information about arepresentation related to a component. The Representation element mayinclude a rep_id attribute (or id attribute) that identifies arepresentation.

For example, the first Representation element may include a value of therep_id attribute which has a value of “rep_v1”, the secondRepresentation element may include a value of the rep_id attribute whichhas a value of “rep_v2”, the third Representation element may include avalue of the rep_id attribute which has a value of “rep_a1”, and thefourth Representation element may include a value of the rep_idattribute which has a value of “rep_a2”.

The S-LSID may include at least one RS element (ROUTE session element)which includes information about a ROUTE session for the service(Srv#1). Each ROUTE session element may include at least one TS element(LCT session element) which includes information about an LCT session.

Each TS element may include a tsi attribute and an appID element. Thetsi attribute may identify an LCT session. The appID element may bereferred to as a ContentInfo element. The ContentInfo element mayinclude additional information mapped to a service (or applicationservice) transmitted through a transmission session. For example, theContentInfo element may include a Representation ID of DASH contentand/or Adaptation Set parameters of a DASH media representation in orderto select an LCT transmission session for rendering. The RepresentationID is an ID related to a component for a service, and may be referred toas a rep_id attribute.

For example, the RS element may include a first TS element for a videocomponent, a second TS element for an audio component, and/or a third TSelement for SLS information.

A tsi element included in the first TS element may have a value of“tsi-v”, and an appID element may have a value of “rep_v1”. A tsielement included in the second TS element may have a value of “tsi-a”,and an appID element may have a value of “rep_a1”. A tsi elementincluded in the third TS element may have a value of “tsi-sls”.

FIG. 86 is a diagram illustrating a form in which a WARN message and aCAP message are transmitted through an EAC according to an embodiment ofthe present invention.

A broadcast transmitter according to an embodiment of the presentinvention may transmit a PLS, an FIT (or SLT), an emergency alertmessage, service data, and SLS. Content related to the FIT (or SLT), theservice data, and the SLS is the same as the above description.Hereinafter, differences will be mainly described.

A PLS according to an embodiment of the present invention may at leastone of an EAC_Flag field, an EA_data_Type field, a WARN_data_versionfield, a WARN_data_target field, a WARN_data_Length field, and/or aCAP_message_info( ) field. Content about signaling information includedin the PLS is the same as the above description.

For example, the EAC_Flag field may have a value of“true” to indicatethat an EAC is present.

In addition, the EA_data_Type field may have a value of “1” to indicatethat a type of an emergency alert message is “WARN+CAP”. In this case,the emergency alert message may include a WARN message and a CAPmessage.

In addition, the WARN_data_version field may have a value of “1”.

In addition, the WARN_data_target field may have a value of “I” toindicate that target information of a WARN message (or WARN data) is“Imminent threats to safety or life”.

In addition, the WARN_data_Length field may have a value of “90” toindicate that a length of a WARN message is “90”.

In addition, the CAP_message_info( ) field may include informationrelated to a CAP message. For example, the CAP_message_info( ) field mayinclude at least one of message_id that identifies a CAP_message_info( )field message and/or a CAP message encoding type field that indicates anencoding type of the CAP message.

The broadcast transmitter according to the embodiment of the presentinvention may transmit the WARN message and the CAP message through adesignated PLP. In this instance, the PLP designated to transmit theWARN message and the CAP message may be referred to as an EAC. In otherwords, the EAC may be a dedicated PLP for transmitting only a physicallayer frame including the WARN message and the CAP message.

For example, when the broadcast transmitter transmits both the WARNmessage and the CAP message, the broadcast transmitter may transmit theWARN message corresponding to a length of “90” indicated by theWARN_data_Length field, and transmit the CAP message after the datalength.

FIG. 87 is a diagram illustrating a link layer header according to anembodiment of the present invention.

The figure illustrates a header structure of a link layer packetaccording to an embodiment of the present invention. Content about eachfield of a header of the link layer packet may include all of the abovedescription. Hereinafter, differences will be mainly described.

An embodiment of the present invention may provide a method oftransmitting a WARN message through link layer signaling. In order forthe broadcast transmitter to transmit the WARN message as one link layerpacket, an LLS packet header may include information that indicates atype of the WARN message.

For example, the LLS packet header according to the present embodimentmay include a signaling_class field and an information_type field. Thesignaling_class field and/or the information_type field may indicate atype of the WARN message.

The signaling_class field indicates a type of signaling informationincluded in the link layer packet, in particular, a payload of the linklayer packet. When a type of signaling information transmitted in thepacket is determined by a value of the signaling_class field, theinformation_type field indicates a type of data transmitted in a payloadof the packet (that is, a target of the WARN message) with regard to thedetermined signaling information. In addition, specific information maybe additionally included according to data type.

FIG. 88 is a diagram illustrating a signaling_class field according toan embodiment of the present invention.

For example, when a value of the signaling_class field is “000”, thevalue indicates that a packet includes signaling information (e.g., SLT)for channel scanning and service acquisition. When a value of thesignaling_class field is “001”, the value indicates that the packetincludes signaling information for a CAP message (or an EAS message oran emergency alert). When a value of the signaling_class field is “010”,the value indicates that the packet includes signaling information forheader compression.

In addition, when a value of the signaling_class field according to thepresent embodiment is “011”, the value indicates that the packetincludes signaling information for a WARN message.

When a value of the signaling_class field according to the presentembodiment is “011”, the packet is referred to as a WARN message packet.

FIG. 89 is a diagram illustrating an information_type field according toan embodiment of the present invention.

When the signaling_class field indicates that a corresponding packetincludes signaling information for a WARN message, the information_typefield indicates a type of data transmitted in a payload of the packet(that is, a target of the WARN message) with regard to determinedsignaling information.

That is, the information_type field may indicate target information ofthe transmitted WARN message (or WARN data).

For example, when a value of the information_type field is “000”, thetarget information of the WARN message (or WARN data) may indicate“Communities of Amber Alerts”. In addition, when a value of theinformation_type field is “001”, the target information of the WARNmessage (or WARN data) may indicate “Imminent threats to safety orlife”. In addition, when a value of the information_type field is “010”,the target information of the WARN message (or WARN data) may indicate“Presidential Alerts via geographically-targeted”. A value of theinformation_type field is not fixed, and may be changed.

FIG. 90 is a diagram illustrating syntax related to a WARN message addedto PLS according to an embodiment of the present invention.

When the broadcast transmitter transmits a WARN message (or WARND) in alink layer packet, PLS according to an embodiment of the presentinvention may include signaling information for the WARN message.

For example, the PLS according to the embodiment of the presentinvention may include at least one of an EAC_Flag field, aWARN_data_version field, and/or a WARN_PLP_ID field.

The EAC_Flag field may indicate whether an EAC is present in a PHYframe. For example, when a value of the EAC_Flag field is “true”, theEAC may be present in the physical frame. When a value of the EAC_Flagfield is “false”, the EAC may not be present in the physical frame.

The WARN_data_version field may indicate a version of the WARN message(or WARN data) transmitted in the PLP.

The WARN_PLP_ID field may indicate a PLP identifier (or PLP ID) thatidentifies a PLP which transmits the WARN message in the PHY frame.

In addition, when the WARN message (or WARND) is transmitted in the linklayer packet, and the WARN message is transmitted through a base PLP,the PLS may not include WARN_PLP_ID. Since the base PLP is a PLP whichis decoded at all times, the PLS may not include the WARN_PLP_ID field.The broadcast receiver may receive and acquire the WARN messagetransmitted through the base PLP.

FIG. 91 is a diagram illustrating a form in which a WARN message istransmitted through LLS according to an embodiment of the presentinvention.

A broadcast transmitter according to an embodiment of the presentinvention may transmit PLS, an FIT (or SLT), an emergency alert message,service data, and SLS. The FIT (or SLT), the service data, and the SLSare the same as described above. Hereinafter, differences will be mainlydescribed.

The PLS according to the present embodiment may include signalinginformation for the WARN message. The PLS may include at least one of anEAC_Flag field, a WARN_data_version field, and/or a WARN_PLP_ID field.The signaling information included in the PLS is the same as describedabove.

For example, the EAC_Flag field may have a value of “false” to indicatethat an EAC is not present in a PHY frame. That is, the WARN message maynot be transmitted through an EAC and may be transmitted through theLLS.

In addition, the WARN_data_version field may have a value of “01” toindicate that a version of the WARN message (or WARN data) is “01 I”.

In addition, the WARN_PLP_ID field may have a value of “#E” to indicatethat an ID of a PLP that transmits the WARN message is “#E”.

The WARN message may be transmitted through link layer signaling. TheWARN message (or WARND) and/or a CAP message (or EAS message, EAD) maybe transmitted through a PLP. For example, the WARN message and/or theCAP message may be transmitted through a base PLP and/or a general PLP(or a general data pipe). Signaling information for the WARN message andthe CAP message may be included in the PLS.

FIG. 92 is a diagram illustrating PLS in a case in which signalinginformation for a WARN message is transmitted through an EAC accordingto an embodiment of the present invention.

Even though the WARN message according to the present embodiment istransmitted in a link layer packet, the signaling information for theWARN message may be transmitted through the EAC. In addition, signalinginformation for the EAC may be included in the PLS.

Referring to the figure, the PLS may include an EAC_Flag field. Thesignaling information included in the PLS is the same as describedabove.

For example, the EAC_Flag field may have a value of“true” to indicatethat the EAC is present in a PHY frame. In addition, an EAT of the EACmay include information that signals a position at which the WARNmessage is transmitted. In addition, the WARN message may not betransmitted through the EAC, and may be transmitted through LLS.

FIG. 93 is a diagram illustrating an EAT that includes signalinginformation for a WARN message according to an embodiment of the presentinvention.

The broadcast transmitter may transmit the EAT through an EAC. Afterentering the EAC, the broadcast receiver may acquire the EAT transmittedthrough the EAC, and acquire transmission path information of the WARNmessage from the EAT.

Referring to the figure, the EAT may include at least one of a table_idfield, a version_number field, a num_EA_data field, an EA_data_typefield, a PLP_ID field, and/or a data_version field.

The table_id field may indicate an ID (or table ID) that identifies theEAT transmitted through the EAC.

The version_number field may indicate a version number of the EAT.

The num_EA_data field may indicate the number of emergency alertmessages described in the EAT.

The EA_data_type field may indicate a data type of an emergency alertmessage described in the EAT. For example, when a value of theEA_data_type field is “00”, the data type of the emergency alert messagemay indicate “unspecified”. In addition, when a value of theEA_data_type field is “01”, the data type of the emergency alert messagemay indicate the “WARN message”. When a value of the EA_data_type fieldis “01”, the data type of the emergency alert message may indicate a“CAP message”.

A value of the EA_data_type field may be assigned as described above,and a remaining value may be assigned based on a possibility that a newtype may be added in the future. Information that needs to be notifiedwhen a transmission path of the emergency alert message is signaled mayvary for each type.

When a value of the EA_data_type field is “01”, the EAT may include atleast one of the PLP_ID field and/or the data_version field.

The PLP_ID field may indicate a PLP identifier (or PLP ID) thatidentifies a PLP which transmits the WARN message in a corresponding PHYframe.

The data_version field may indicate a version of the WARN message (orWARN data) transmitted through the PLP.

FIG. 94 is a diagram illustrating a form in which signaling informationfor a WARN message is transmitted through an EAC according to anembodiment of the present invention.

A broadcast transmitter according to an embodiment of the presentinvention may transmit PLS, an FIT (or SLT), an EAT, an emergency alertmessage, service data, and SLS. The FIT (or SLT), the service data, andthe SLS are the same as described above. Hereinafter, differences willbe mainly described.

The PLS according to the present embodiment may include signalinginformation for the WARN message. The PLS may include an EAC_Flag field.The signaling information included in the PLS is the same as describedabove. For example, the EAC_Flag field may have a value of “true” toindicate that an EAC is present in a corresponding PHY frame. That is,most signaling information for the WARN message may be transmittedthrough the EAC, and the WARN message may be transmitted through LLS.

The EAT according to the present embodiment may be transmitted throughthe EAC. The EAT may indicate a type and a transmission path of theemergency alert message. The EAT may include an EA_data_type field, adata_version field, and/or a PLP_ID field.

For example, a value of the EA_data_type field may be “01”, and theEA_data_type field may indicate that a data type of the emergency alertmessage is the “WARN message”. In addition, the data_version field mayindicate that a version of the WARN message (or WARN data) transmittedthrough a PLP is “01”. In addition, the PLP_ID field may indicate thatan ID of the PLP that transmits the WARN message in a corresponding PHYframe is “#EA”.

The WARN message according to the present embodiment may be transmittedin a link layer packet. The WARN message may be transmitted through ageneral PLP (or general data pipe). An ID of the general PLP throughwhich the WARN message is transmitted may be “#EA” which is indicated bythe PLP_ID field.

FIG. 95 is a diagram illustrating PLS that includes signalinginformation for a WARN message according to an embodiment of the presentinvention.

The WARN message according to the present embodiment may be transmittedthrough an LCT session. In addition, the signaling information for theWARN message may be included in the PLS. For example, the PLS mayinclude information about a path through which the WARN message istransmitted and attribute information of the WARN message.

Referring to the figure, the PLS may include at least one of anum_EA_data field, an EA_data_Type field, a WARN_data_version field, aWARN_data_target field, a sourceIPaddress field, a destIPaddress field,a destPort field, a tsi field, a PLP_ID field, a WARN_data_Length field,and/or a CAP_message_info( ) field.

The num_EA_data field may indicate the number of transmitted emergencyalert messages (or emergency alert data). A “for” loop subsequent to thenum_EA_data field may include content related to emergency alert data,the number of which is indicated by a value of the num_EA_data field.

The EA_data_Type field may indicate a type of an emergency alertmessage. For example, when a value of the EA_data_Type field is “00”, atype of an emergency alert message may be “WARN only”. In this case, theemergency alert message may include only the WARN message. In addition,the PLS may include the WARN_data_version field, the WARN_data_targetfield, the sourceIPaddress field, the destIPaddress field, the destPortfield, the tsi field, and the PLP_ID field.

In addition, when a value of the EA_data_Type field is “01”, a type ofan emergency alert message may be “WARN+CAP”. In this case, theemergency alert message may include the WARN message and the CAPmessage. In addition, the PLS may include the WARN_data_version field,the WARN_data_target field, the sourceIPaddress field, the destIPaddressfield, the destPort field, the tsi field, the PLP_ID field, theWARN_data_Length field, and the CAP_message_info( ) field.

In addition, when a value of the EA_data_Type field is “10”, a type ofan emergency alert message may be “CAP only”. In this case, theemergency alert message may include only the CAP message. In addition,the PLS may include the CAP_message_info( ) field.

The WARN_data_version field may indicate a version of a transmitted WARNmessage (or WARN data).

The WARN_data_target field may indicate target information of thetransmitted WARN message (or WARN data).

The sourceIPaddress field may indicate a source IP address of a sessionin which the WARN message is transmitted.

The destIPaddress field may indicate a destination IP address of asession in which the WARN message is transmitted.

The destPort field may indicate a destination port number of a sessionin which the WARN message is transmitted.

The tsi field may indicate an ID of an LCT session through which theWARN message is transmitted.

The PLP_ID field may indicate an ID of a PLP through which the WARNmessage is transmitted.

The WARN_data_Length field may indicate length information of the WARNmessage.

The CAP_message_info( ) field may include CAP message information. Forexample, the CAP_message_info( ) field may include at least one of amessage_id field that identifies a CAP_message_info( ) field messageand/or a CAP message encoding type field that indicates an encoding typeof the CAP message.

FIG. 96 is a diagram illustrating a form in which a WARN message istransmitted through an LCT session according to an embodiment of thepresent invention.

A broadcast transmitter according to an embodiment of the presentinvention may transmit PLS, an FIT (or SLT), an emergency alert message,service data, and SLS. The FIT (or SLT), the service data, and the SLSare the same as described above. Hereinafter, differences will be mainlydescribed.

The PLS according to the present embodiment may include signalinginformation for the WARN message. The PLS may include at least one of anEAC_Flag field, a WARN_data_version field, a WARN_data_target field, aWARN_PLP_ID field, a sourceIPaddress field, a destIPaddress field, adestPort field, and/or a tsi field. The signaling information includedin the PLS is the same as described above.

For example, the EAC_Flag field may have a value of “false” to indicatethat an EAC is not present in a corresponding PHY frame. That is, theWARN message may not be transmitted through an EAC, and the WARN messagemay be transmitted through the LCT session.

In addition, the WARN_data_version field may have a value of “3”.

In addition, the WARN_data_target field may have a value of “10” toindicate that target information of the WARN message is “PresidentialAlerts via geographically-targeted”.

In addition, the WARN_PLP_ID field may have a value of “#E” to indicatethat an ID of a PLP that transmits the WARN message is “#E”.

In addition, the sourceIPaddress field may have a value of “0”, thedestIPaddress field may have a value of “0”, and the destPort field mayhave a value of “0”. The sourceIPaddress field, the destIPaddress field,and the destPort field may uniquely identify a session (or ROUTEsession) through which the WARN message is transmitted.

In addition, the tsi field may have a value of “tsi-warn” to indicatethat an ID of an LCT session through which the WARN message istransmitted is “tsi-warn”.

The WARN message according to the present embodiment may be transmittedthrough the LCT session. One ROUTE session may include at least one LCTsession. The ROUTE session may be transmitted through at least one PLP.For example, signaling information that indicates a path through whichthe WARN message is transmitted may be included in the PLS. The WARNmessage may be transmitted through a PLP, a ROUTE session, and/or an LCTsession identified by the signaling information included in the PLS. AROUTE session through which the WARN message is transmitted may bedifferent from a ROUTE session through which service data and/or SLS istransmitted. In addition, a PLP through which the WARN message istransmitted may be different from a PLP through which service dataand/or SLS is transmitted.

FIG. 97 is a diagram illustrating an EAT in a case in which signalinginformation for a WARN message is transmitted through an EAC accordingto an embodiment of the present invention.

The WARN message according to the present embodiment may be transmittedthrough an LCT session. In addition, the signaling information for theWARN message (for example, information about a path through which theWARN message is transmitted) may be included in the EAT of the EAC. Inthis case, signaling information for the EAC may be included in PLS.

Referring to the figure, the EAT according to the present embodiment mayinclude at least one of a table_id field, a version_number field, anum_EA_data field, an EA_data_type field, a data_version field, adata_target field, a sourceIPaddress field, a destIPaddress field, adestPort field, a PLP_ID field, and/or a tsi field.

The table_id field may indicate an ID (or table ID) that identifies theEAT transmitted through the EAC.

The version_number field may indicate a version number of the EAT.

The num_EA_data field may indicate the number of emergency alertmessages described in the EAT.

The EA_data_type field may indicate a data type of an emergency alertmessage described by the EAT. For example, when a value of theEA_data_type field is “01”, the data type of the emergency alert messagemay indicate the “WARN message”.

The data_version field may indicate a version of the WARN message whichis transmitted through a PLP.

The data_target field may indicate target information of the transmittedWARN message.

The sourceIPaddress field may indicate a source IP address of a sessionthrough which the WARN message is transmitted.

The destIPaddress field may indicate a destination IP address of asession through which the WARN message is transmitted.

The destPort field may indicate a destination port number of a sessionthrough which the WARN message is transmitted.

The PLP_ID field may indicate a PLP identifier (or PLP ID) thatidentifies a PLP which transmits the WARN message in a corresponding PHYframe.

The tsi field may indicate an ID of a transmitted LCT session of an LCTsession in which the WARN message is transmitted.

FIG. 98 is a diagram illustrating a form in which signaling informationfor a WARN message is transmitted through an EAC according to anembodiment of the present invention.

A broadcast transmitter according to an embodiment of the presentinvention may transmit PLS, an FIT (or SLT), an EAT, an emergency alertmessage, service data, and SLS. The FIT (or SLT), the service data, andthe SLS are the same as described above. Hereinafter, differences willbe mainly described.

The PLS according to the present embodiment may include signalinginformation for the EAC. The PLS may include an EAC_Flag field. Thesignaling information included in the PLS is the same as describedabove.

For example, the EAC_Flag field may have a value of“true” to indicatethat an EAC is present in a corresponding PHY frame. That is, thesignaling information for the WARN message may be transmitted throughthe EAT of the EAC, and the WARN message may be transmitted through anLCT session.

The EAT according to the present embodiment may be transmitted throughthe EAC. For example, the EAT may include at least one of anEA_data_type field, a data_version field, a data_target field, asourceIPaddress field, a destIPaddress field, a destPort field, a PLP_IDfield, and/or a tsi field.

A value of the EA_data_type field may be “00”, and a type of theemergency alert message may be “WARN only”. In this case, the emergencyalert message may include only the WARN message.

In addition, a value of the data_version field may be “01”.

In addition, a value of the data_target field may be “10”, and targetinformation of the WARN message may indicate “Presidential Alerts viageographically-targeted”.

In addition, a value of the PLP_ID field may be “#1”, and the PLP_IDfield may indicate that an ID of a PLP that transmits the WARN messageis “#E”.

In addition, a value of the sourceIPaddress field may be “#1”, a valueof the destIPaddress field may be “# I”, and a value of the destPortfield may be “#1”. The sourceIPaddress field, the destIPaddress field,and the destPort field may uniquely identify a ROUTE session throughwhich the WARN message is transmitted.

In addition, a value of the tsi field may be “tsi-warm”, and the tsifield may indicate that the WARN message is transmitted through an LCTsession identified by “tsi-warn”.

The WARN message according to the present embodiment may be transmittedthrough the LCT session.

Referring to the figure, the WARN message, the service data, and servicelayer signaling information may be transmitted through one ROUTE session(dIP1/dPort1/sIP1). The ROUTE session (dIP1/dPort1/sIP1) may betransmitted through one PLP (#1). In addition, the ROUTE session(dIP1/dPort1/sIP1) may include an LCT session (tsi-warn) that transmitsthe WARN message, an LCT session (tsi-v) that transmits a videocomponent, an LCT session (tsi-a) that transmits an audio component, andan LCT session (tsi-sls) that transmits the service layer signalinginformation.

FIG. 99 is a diagram illustrating a form in which a WARN message istransmitted through a dedicated PLP or a dedicated LCT session accordingto an embodiment of the present invention.

An embodiment of the present invention may use a PLP ID designated forPrivate Data Stream Delivery, a designated LCT session ID, or an IDvalue that may be assigned to a corresponding protocol.

For example, the WARN message may be transmitted through a dedicated PLPin which a value of a PLP ID is “#911”. In addition, the WARN messagemay be transmitted through a dedicated LCT session in which a value ofan LCT session ID is “tsi-911”. When the WARN message is transmittedthrough the dedicated PLP or the dedicated LCT session, the broadcastreceiver may receive the WARN message transmitted through the dedicatedPLP or the dedicated LCT session, and immediately process the WARNmessage.

FIG. 100 is a diagram illustrating a broadcast transmission methodaccording to an embodiment of the present invention.

A broadcast transmitter according to an embodiment of the presentinvention may include a controller and/or a transmitting unit.

The broadcast transmitter according to the present embodiment maygenerate service data using the controller (CS1000100).

Then, the broadcast transmitter according to the present embodiment maygenerate signaling data using the controller (CS1000200).

Then, the broadcast transmitter according to the present embodiment maytransmit a broadcast signal including the service data and the signalingdata using the transmitting unit (CS1000300).

The broadcast transmitter may encapsulate an emergency alert message andthe signaling data in a link layer packet using the controller. Inaddition, the broadcast transmitter may transmit a broadcast signalincluding the link layer packet.

The signaling data may include bootstrapping information that supportsbootstrapping of service acquisition. For example, the signaling datamay include low level signaling data, and the low level signaling datamay include an FIT and/or an SLT.

The signaling data may include a broadcaster ID that identifies abroadcaster related to a service. For example, the broadcaster IDincluded in the signaling data may refer to a partition_id fieldincluded in the FIT and/or the SLT.

The emergency alert message may include a broadcaster ID that identifiesa broadcaster related to the emergency alert message. For example, thebroadcaster ID included in the emergency alert message may refer to apartition_id field included in an EAT.

According to an embodiment of the present invention, the partition_idfield included in the FIT and/or the SLT may be matched to thepartition_id field included in the EAT. Therefore, the broadcastreceiver may receive the emergency alert message based on thepartition_id field included in the FIT and/or the SLT and thepartition_id field included in the EAT.

The signaling data may further include category information thatindicates a category of the service. For example, the categoryinformation may refer to a service_category field. For example, theservice_category field may indicate one of an A/V service, an audioservice, an ESG service, a Content on Demand (CoD) service, an app-basedservice, and/or an emergency alert message (EAM) service (or EASservice).

The signaling data may further include the emergency alert message. Forexample, the emergency alert message may be transmitted through linklayer signaling. In addition, the emergency alert message may beincluded in the signaling data and transmitted.

The emergency alert message may further include a message ID thatidentifies the emergency alert message. For example, the message ID mayrefer to an EAS_message_id field.

The link layer packet may include a header and a payload. In addition,the header may include a first header having a fixed length and a secondheader having a variable length. In addition, the first header mayinclude type information that indicates a packet type of input data, andthe first header may further include configuration information thatindicates a configuration of the payload. For example, the typeinformation may refer to a packet type field. In addition, theconfiguration information may refer to a payload_config field.

A broadcast signal according to an embodiment of the present inventionmay be shared by a plurality of broadcasters. That is, the broadcastersmay use a portion of the broadcast signal or the whole broadcast signalto broadcast a service. For example, the plurality of broadcasters mayshare one frequency.

In addition, the broadcast signal may include a plurality of emergencyalert messages transmitted from the plurality of broadcasters.

For example, the plurality of broadcasters may include a firstbroadcaster and a second broadcaster. An emergency alert messagetransmitted from the second broadcaster may include an emergency alertmessage for the first broadcaster.

Even when the broadcast receiver provides a service transmitted from thefirst broadcaster to a user, the broadcast receiver may provide theemergency alert message transmitted from the second broadcaster to theuser.

FIG. 101 is a diagram illustrating a broadcast reception methodaccording to an embodiment of the present invention.

A broadcast receiver according to an embodiment of the present inventionmay include a controller and/or a broadcast receiving unit.

The broadcast receiver according to the embodiment of the presentinvention may receive a broadcast signal including service data andsignaling data using the broadcast receiving unit (CS1010100).

The broadcast receiver according to the embodiment of the presentinvention may acquire the signaling data using the controller(CS1010200).

Then, the broadcast receiver according to the embodiment of the presentinvention may acquire the service data based on the signaling data usingthe controller (CS1010300).

In addition, the broadcast receiver may receive a broadcast signalincluding a link layer packet. Then, the broadcast receiver maydecapsulate the link layer packet into an emergency alert message andthe signaling data using the controller.

The signaling data may include bootstrapping information that supportsbootstrapping of service acquisition. For example, the signaling datamay include low level signaling information, and the low level signalinginformation may include an FIT and/or an SLT.

The signaling data may include a broadcaster ID that identifies abroadcaster related to a service. For example, the broadcaster IDincluded in the signaling data may refer to a partition_id fieldincluded in the FIT and/or the SLT.

The emergency alert message may include a broadcaster ID that identifiesa broadcaster related to the emergency alert message. For example, thebroadcaster ID included in the emergency alert message may refer to apartition_id field included in an EAT.

According to an embodiment of the present invention, the partition_idfield included in the FIT and/or the SLT may match the partition_idfield included in the EAT. Therefore, the broadcast receiver may receivethe emergency alert message based on the partition_id field included inthe FIT and/or the SLT and the partition_id field included in the EAT.

The signaling data may further include category information thatindicates a category of the service. For example, the categoryinformation may refer to a service_category field. For example, theservice_category field may indicate one of an A/V service, an audioservice, an ESG service, a CoD service, an app-based service, and/or anEAM service (or EAS service).

The signaling data may further include the emergency alert message. Forexample, the emergency alert message may be transmitted through linklayer signaling. In addition, the emergency alert message may beincluded in the signaling data and transmitted.

The emergency alert message may further include a message ID thatidentifies the emergency alert message. For example, the message ID mayrefer to an EAS_message_id field.

The link layer packet may include a header and a payload. In addition,the header may include a first header having a fixed length and a secondheader having a variable length. In addition, the first header mayinclude type information that indicates a packet type of input data, andthe first header may further include configuration information thatindicates a configuration of the payload. For example, the typeinformation may refer to a packet type field. In addition, theconfiguration information may refer to a payload_config field.

A broadcast signal according to an embodiment of the present inventionmay be shared by a plurality of broadcasters. That is, a broadcaster mayuse a portion of the broadcast signal or the whole broadcast signal tobroadcast a service. For example, the plurality of broadcasters mayshare one frequency.

In addition, the broadcast signal may include a plurality of emergencyalert messages transmitted from the plurality of broadcasters.

For example, the plurality of broadcasters may include a firstbroadcaster and a second broadcaster. An emergency alert messagetransmitted from the second broadcaster may include an emergency alertmessage for the first broadcaster.

Even when the broadcast receiver provides a service transmitted from thefirst broadcaster to a user, the broadcast receiver may provide theemergency alert message transmitted from the second broadcaster to theuser.

Modules or units may be processors executing consecutive processesstored in a memory (or a storage unit). The steps described in theaforementioned embodiments can be performed by hardware/processors.Modules/blocks/units described in the above embodiments can operate ashardware/processors. The methods proposed by the present invention canbe executed as code. Such code can be written on a processor-readablestorage medium and thus can be read by a processor provided by anapparatus.

While the embodiments have been described with reference to respectivedrawings for convenience, embodiments may be combined to implement a newembodiment. In addition, designing computer-readable recording mediumstoring programs for implementing the aforementioned embodiments iswithin the scope of the present invention.

The apparatus and method according to the present invention are notlimited to the configurations and methods of the above-describedembodiments and all or some of the embodiments may be selectivelycombined to obtain various modifications.

The methods proposed by the present invention may be implemented asprocessor-readable code stored in a processor-readable recording mediumincluded in a network device. The processor-readable recording mediumincludes all kinds of recording media storing data readable by aprocessor. Examples of the processor-readable recording medium include aROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical datastorage device and the like, and implementation as carrier waves such astransmission over the Internet. In addition, the processor-readablerecording medium may be distributed to computer systems connectedthrough a network, stored and executed as code readable in a distributedmanner.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims. Such modifications should notbe individually understood from the technical spirit or prospect of thepresent invention.

Both apparatus and method inventions are mentioned in this specificationand descriptions of both the apparatus and method inventions may becomplementarily applied to each other.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent invention. Therefore, the scope of the invention should bedetermined by the appended claims and their legal equivalents, not bythe above description, and all changes coming within the meaning andequivalency range of the appended claims are intended to be embracedtherein.

In the specification, both the apparatus invention and the methodinvention are mentioned and description of both the apparatus inventionand the method invention can be applied complementarily.

Various embodiments have been described in the best mode for carryingout the invention.

INDUSTRIAL APPLICABILITY

The present invention is applied to broadcast signal providing fields.

Various equivalent modifications are possible within the spirit andscope of the present invention, as those skilled in the relevant artwill recognize and appreciate. Accordingly, it is intended that thepresent invention cover the modifications and variations of thisinvention provided they come within the scope of the appended claims andtheir equivalents.

The invention claimed is:
 1. A broadcast transmission method comprising:generating an emergency alert message for an emergency alert service,the emergency alert message including a message identifier (ID) foridentifying the emergency alert message and a service ID identifying aservice related to the emergency alert message; encapsulating theemergency alert message and service data into a plurality of link layerpackets; physical layer processing the plurality of link layer packetsto a plurality of data pipes to form a signal frame of a broadcastsignal, wherein data in each of the plurality of data pipes is processedwith a specific code rate, the physical layer processing including: timeinterleaving data in a data pipe according to a first mode or a secondmode, wherein the first mode represents that the time interleaving isperformed based on a convolutional interleaving operation, the secondmode represents that the time interleaving is performed based on acombination of a block interleaving operation and the convolutionalinterleaving operation; and transmitting the broadcast signal, whereinthe broadcast signal further includes physical layer signalinginformation, the physical layer signaling information including asignaling field indicating whether at least one data pipe of theplurality of data pipes carries the emergency alert message and timeinterleaving signaling information related to the first mode and thesecond mode.
 2. The method of claim 1, wherein the at least one datapipe further carries service signaling data that includes bootstrappinginformation supporting bootstrapping of service acquisition, and thesignaling data includes a broadcaster ID identifying a broadcasterrelated to a service.
 3. The method of claim 1, wherein the broadcastsignal is shared by a plurality of broadcasters, and the broadcastersuse all or a portion of the broadcast signal to broadcast a service. 4.The method of claim 3, wherein the broadcast signal further includes aplurality of emergency alert messages transmitted from the plurality ofbroadcasters.
 5. The method of claim 4, wherein the plurality ofbroadcasters include a first broadcaster and a second broadcaster, andan emergency alert message transmitted from the second broadcasterincludes an emergency alert message for the first broadcaster.
 6. Abroadcast reception method comprising: physical layer processing abroadcast signal carrying a signal frame, the signal frame including aplurality of data pipes carrying a plurality of link layer packets andphysical layer signaling information, the physical layer processingcomprising: decoding physical layer signaling information included inthe signal frame for decoding the plurality of data pipes, wherein thephysical layer signaling information includes a signaling fieldindicating whether at least one data pipe of the plurality of data pipescontains an emergency alert message, the physical layer signalinginformation including time deinterleaving signaling information timerelated to a first mode and a second mode, the first mode representsthat a time deinterleaving operation includes a convolutionaldeinterleaving operation, and the second mode represents that the timedeinterleaving operation includes a combination of a convolutionaldeinterleaving operation and a block deinterleaving operation; timedeinterleaving data in a data pipe based on the time deinterleavingsignaling information; and decoding data in each of the plurality ofdata pipes by a specific code rate to output the plurality of link layerpackets; and decapsulating the plurality of link layer packets intoservice data and the emergency alert message, the emergency alertmessage including a message identifier (ID) for identifying theemergency alert message and a service ID identifying a service relatedto the emergency alert message.
 7. The method of claim 6, wherein the atleast one data pipe further carries service signaling data that includesbootstrapping information supporting bootstrapping of serviceacquisition, and the signaling data includes a broadcaster IDidentifying a broadcaster related to a service.
 8. The method of claim6, wherein the broadcast signal is shared by a plurality ofbroadcasters, and the broadcasters use all or a portion of the broadcastsignal to broadcast a service.
 9. The method of claim 8, wherein thebroadcast signal further includes a plurality of emergency alertmessages transmitted from the plurality of broadcasters.
 10. The methodof claim 9, wherein the plurality of broadcasters include a firstbroadcaster and a second broadcaster, and an emergency alert messagetransmitted from the second broadcaster includes an emergency alertmessage for the first broadcaster.